The composite cathode of a solid-state battery is a dense, non-porous blend of active material, conductive additive and a portion of solid electrolyte known as the catholyte. Unlike conventional lithium-ion cells, where a liquid electrolyte seeps into every pore, the solid-state version has no pore-filling liquid to rescue poor contacts. Every particle must touch its neighbour intimately, and both ions and electrons need homogeneous, percolating pathways through the electrode. The conductive additive in this study is Super C65, a carbon black from Imerys, which must form an unbroken electronic network threading through the cathode. The active material is carbon-coated lithium iron phosphate, or LFP, whose own carbon coating enhances intrinsic electronic conductivity and interfacial lithium transfer. The researchers were careful to distinguish between these two carbons: the factory-applied coating on the LFP particles and the C65 introduced during electrode processing behave very differently under the forces of mixing.

To isolate the effects of processing, the team prepared slurries under dry-room conditions with a dew point below minus 60 degrees Celsius, using a bead mill to first dissolve LiTFSI in acetonitrile and then mix in high molecular weight PEO to form the catholyte. The LFP and C65 powders were dry-mixed in a planetary vacuum mixer at 200, 750 or 1500 revolutions per minute, and the resulting powder blend was then wet-mixed into the catholyte for 60, 120 or 180 minutes. Five slurries were produced in total, each cast onto carbon-coated aluminium current collectors and dried under vacuum. Crucially, the researchers deliberately skipped calendering, the mechanical compaction step common in electrode manufacturing, so that the morphological fingerprints left by the mixing process itself would remain visible in the finished electrodes.

One of the study’s most elegant methodological contributions is the introduction of a relative viscosity parameter. Batch-to-batch variability in the PEO raw material, stemming from differences in molecular weight distribution, meant that absolute viscosity measurements could not be compared reliably across samples. By normalizing the slurry viscosity to the viscosity of the corresponding catholyte at the end of its own mixing, the team could decouple the true effects of mixing time and speed from uncontrolled fluctuations in the polymer feedstock. Validation experiments with four separate preparations, including three different PEO batches, confirmed that this normalization substantially reduced variability, offering a practical tool that other laboratories can adopt to make their slurry comparisons meaningful.

The rheological results revealed a counterintuitive trend. Longer wet mixing times and higher dry mixing speeds both reduced slurry viscosity, and the researchers traced this not to further polymer degradation but to the progressive deagglomeration of the carbon black. Gel permeation chromatography showed that the PEO molecular weight decreased exponentially toward a plateau, with an apparent scission-rate constant of 7.49 times ten to the minus seven per minute, but since total mixing times stayed below the point where degradation becomes negligible, the viscosity drop had to come from elsewhere. As C65 agglomerates break apart, the number of carbon particles rises, promoting immobilization of polymer chains and reducing chain entanglement, a mechanism previously described by Hoffman and colleagues. More effective deagglomeration also increases interparticle volume, allowing more solvent molecules to occupy the spaces between carbon particles and thereby lowering the suspension viscosity.

These rheological differences translated directly into electrode microstructure. Scanning electron microscopy of surfaces and argon ion-milled cross-sections, analysed with ImageJ, showed that longer wet mixing produced electrodes with lower porosity, higher active material loading and fewer surface lumps, because lower viscosity allows better particle rearrangement and compaction during drying. In the dry mixing series, the sample processed at 1500 rpm displayed the most homogeneous morphology, while the 200 rpm sample exhibited a highly cracked surface, suggesting that large C65 agglomerates weaken the mechanical integrity of the composite cathode and hinder uniform polymer distribution. Porosity values ranged from about 1.65 percent for the longest wet mixing time to nearly 3 percent for the mildest conditions, differences that proved consequential for transport properties.

Electronic and ionic conductivity measurements told a more nuanced story. Reference pellets containing as little as 5 weight percent C65 achieved electronic conductivities of roughly ten to the minus two siemens per centimetre, confirming that this modest carbon fraction is sufficient for percolation. Yet after full electrode processing, bulk electronic conductivity dropped by nearly two orders of magnitude at both 25 and 70 degrees Celsius. Wet mixing time had little effect on this bulk conductivity, but in-plane resistivity measurements revealed that excessive wet mixing stresses the carbon particles and degrades the conductive network. In the dry mixing series, the intermediate 750 rpm condition delivered the lowest interfacial resistance and the highest ionic conductivity, while the 1500 rpm sample, despite its denser packing, showed signs of carbon particles being over-stressed and unable to form an optimal network.

Full-cell testing in monolayer pouch cells with lithium metal anodes, cycled at 70 degrees Celsius between 2.6 and 3.7 volts, exposed the trade-offs with striking clarity. At the gentle C/20 rate, all cells delivered similar capacities between 156 and 158 mAh per gram, but at higher rates the mildest processing conditions won out: the 60-minute wet mix and the 200 rpm dry mix, both with the highest slurry viscosities and highest porosities, achieved the highest capacities at C/5. The researchers attribute this to the higher viscosity limiting conductive additive redistribution, thereby preserving a favourable electronic network, while mud cracking in the 200 rpm electrode may have created preferential channels for solid electrolyte infiltration during cycling. However, these high-capacity electrodes also showed the poorest cycle life, with the 200 rpm sample lasting only 65 cycles before coulombic efficiency fell below 98 percent, compared to 120 cycles for the balanced 750 rpm condition.

The degradation mechanism was revealed through X-ray computed micro-tomography of intact pouch cells, a technique that avoids the impossible task of disassembling strongly adhesive cycled cells. Cross-sections of a pristine cell showed homogeneous layers with only minor pores at the cathode-electrolyte interface, but after 130 cycles the lithium metal anode had thinned from 500 to 470 micrometres, voids had multiplied in the cathode, and dark regions appeared within the solid electrolyte layer, signatures of lithium dendrites growing from the anode through the polymer. Grain boundaries in the electrolyte, attributed to solid electrolyte interphase formed by soft dendrites, were also visible. Impedance spectroscopy of the aged cell confirmed diminished ionic diffusion, tying the loss of coulombic efficiency directly to dendrite propagation.

The broader lesson of this work is that in solid-state batteries, processing is not a secondary consideration but a first-order design variable. The optimal wet mixing time of 120 minutes balanced electrode compaction against preservation of the conductive network, while an intermediate dry mixing speed of 750 rpm achieved the best cyclability without compromising lithium-ion transport. Even a small amount of residual porosity, the authors suggest, may serve as stress-relief space accommodating the volume changes of lithium insertion and extraction in a mechanically rigid system. As solid-state batteries edge toward commercialization, this study demonstrates that the path to better cells may run through the mixing vessel, where the fate of every carbon black agglomerate ultimately determines whether electrons and ions can find their way home.

Subject of Research: Effect of slurry mixing parameters on carbon black distribution and performance of solid polymer electrolyte composite cathodes

Article Title: Carbon black distribution in low viscosity polymer slurries

Article References: Carbon black distribution in low viscosity polymer slurries. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: solid-state batteries, carbon black, polymer electrolyte, slurry rheology, composite cathode, lithium metal anode, PEO, LiTFSI, electrode processing, lithium dendrites, X-ray tomography, LFP

The significance of the result lies not just in the headline number but in how it was achieved. Solid polymer electrolytes are prized as replacements for flammable liquid electrolytes in batteries and supercapacitors, but their Achilles heel has always been sluggish ion transport. In most polymer hosts, ions can only move through disordered, amorphous regions where chain segments are mobile enough to open and close pathways. Crystalline regions, by contrast, act as roadblocks. The Iraqi and Turkish team therefore set out to maximize the amorphous fraction of their blend, and glycerol proved to be an extraordinarily effective tool for the job.

X-ray diffraction (XRD) provided the first and most striking piece of evidence. The pristine chitosan/PVP/NaNO₃ film, labeled CPNG-0, showed a degree of crystallinity of 28.3 percent. As glycerol content was increased step by step, that figure fell progressively, dropping to just 6.8 percent in the most plasticized sample, CPNG-40. In other words, glycerol did not merely sit between the polymer chains; it systematically dismantled their ordered packing, enlarging the amorphous phase that serves as the highway for sodium ions. This kind of quantitative, composition-resolved crystallinity data is exactly what the field has needed to connect structure to performance.

Fourier-transform infrared spectroscopy (FTIR) filled in the molecular picture. The characteristic functional-group bands of chitosan, PVP, sodium nitrate, and glycerol all shifted and broadened as the formulations changed, which the authors interpret as evidence of complex formation and enhanced polymer–salt interactions. Hydrogen bonding between glycerol’s hydroxyl groups and the polar sites on the two polymers effectively competes with the polymer–polymer and polymer–salt interactions that would otherwise promote crystallization. The result is a more homogeneous, better-connected matrix in which sodium ions are dissociated from the salt lattice and coordinated loosely enough to hop from site to site.

The electrochemical consequences were dramatic. Electrochemical impedance spectroscopy (EIS) showed the bulk resistance of the films collapsing from 295,600 ohms for the unplasticized CPNG-0 to a mere 18 ohms for CPNG-40. The Nyquist plots told the same story visually: the pristine sample displayed a large semicircle, the classic signature of a highly resistive material dominated by charge-transfer and bulk effects, while the glycerol-rich sample produced a spike-dominated response, indicating that the material had transitioned into a regime of highly efficient ion transport in which the blocking-electrode capacitance dominates the low-frequency behavior.

Dielectric measurements added a further layer of insight. At low frequencies, the glycerol-rich samples exhibited significantly enhanced dielectric constant and dielectric loss, which the researchers attribute to increased accumulation of charge carriers at the electrodes — the well-known phenomenon of electrode polarization. A higher dielectric constant matters because it weakens the Coulombic attraction between dissociated cations and anions, allowing more ions to move freely. The relaxation peak frequency shifted from 0.133 kHz to 133.65 kHz, and the corresponding relaxation time plummeted from 1.196 milliseconds to 1.191 microseconds — a thousand-fold acceleration in the characteristic timescale over which dipoles and ions reorganize in response to an applied field.

Beyond conductivity itself, the team extracted the fundamental ion-transport parameters that govern device performance. Ionic diffusivity, charge-carrier density, and ionic mobility all increased with glycerol loading, a combination that is not always achieved simultaneously. Often, adding a plasticizer increases the number of mobile ions but reduces their mobility, or vice versa; here, both quantities rose together, which explains why the conductivity gain was so large. Argand plot analyses reinforced the picture, showing that ionic relaxation occurs more rapidly and that polymer segmental motion improves as glycerol content increases — a direct link between chain dynamics and ion hopping.

What makes the work particularly timely is the choice of materials. Chitosan is derived from chitin, the structural polymer of crustacean shells and one of the most abundant biopolymers on Earth, while PVP is a water-soluble, biocompatible synthetic polymer. Sodium nitrate provides sodium ions from an element that is vastly more abundant and cheaper than lithium. Together, they point toward electrolytes that are flexible, non-toxic, environmentally benign, and potentially compatible with wearable and implantable electronics. The field of biopolymer electrolytes has been growing rapidly, with recent studies exploring methylcellulose, dextran, starch, and carrageenan hosts, and the new results fit into a broader pattern in which glycerol plasticization consistently emerges as a powerful, low-cost strategy for enhancing ion transport.

The physics of why glycerol works so well is worth unpacking. As a small molecule with three hydroxyl groups, glycerol inserts itself between polymer chains, screening the intermolecular hydrogen bonds and dipole interactions that hold crystallites together. It also lowers the glass-transition temperature of the blend, giving chain segments the thermal mobility they need even at room temperature. Because ion motion in polymer electrolytes is coupled to segmental relaxation — ions effectively surf on the moving chains — faster segmental dynamics translate directly into faster ion transport. Glycerol additionally increases the free volume of the matrix and can solvate sodium cations, further promoting salt dissociation. The combination of amorphous phase enlargement, enhanced segmental motion, and improved salt dissociation is what produced the four-order-of-magnitude conductivity leap reported here.

Challenges remain before such films can power real devices. The authors’ measurements establish structural, dielectric, and electrochemical properties, but translating a laboratory film into a battery or supercapacitor requires demonstrations of long-term cycling stability, electrochemical stability windows, and mechanical robustness under repeated flexing. Nevertheless, the numbers reported — a bulk resistance of just 18 ohms and a conductivity approaching the 10⁻⁴ S/cm range often cited as a practical threshold for electrochemical device applications — make this chitosan/PVP/NaNO₃ system one of the most compelling biopolymer electrolytes described to date. If the recipe’s simplicity holds up at scale, the future of flexible, sustainable energy storage may owe as much to a bottle of glycerol as to any high-tech nanomaterial.

Subject of Research: Glycerol-plasticized chitosan/PVP sodium-ion conducting biopolymer electrolytes

Article Title: Amorphous phase enlargement and boosting the ionic conductivity in glycerolized chitosan/PVP-NaNO3 biopolymer electrolytes

Article References: Mohammed, S. S., Aziz, S. B., Rasul, H. H., Dağdelen, F., & KÖK, M. (2026). Amorphous phase enlargement and boosting the ionic conductivity in glycerolized chitosan/PVP-NaNO3 biopolymer electrolytes. Polymer Bulletin, 83(12), Article 654. https://doi.org/10.1007/s00289-026-06702-0

Image Credits: AI Generated

DOI: 10.1007/s00289-026-06702-0

Keywords: polymer electrolyte, chitosan, PVP, glycerol plasticizer, NaNO3, ionic conductivity, XRD, FTIR, electrochemical impedance spectroscopy, dielectric properties, biopolymer, energy storage

The team, led by Fengxia Zhai, Liqi Zhuang, Xinyu Wei, Fahai Cao, and Shicheng Zhao, worked with sulfonated polyimides, a family of aromatic polymers prized for their thermal stability, mechanical robustness, and film-forming ability. By attaching sulfonic acid groups to the polymer backbone, chemists create the acidic sites that attract water and enable protons to hop through the material. The catch is dosage. To reach conductivities useful in a fuel cell, sulfonated polyimides typically need a high degree of sulfonation, and that very density of acidic groups makes the polymer drink up water voraciously. The membrane swells, its dimensions drift, and over time water attacks the imide linkages themselves, degrading the film hydrolytically until it fails. This long-standing trade-off between conductivity and durability has kept sulfonated polyimides largely out of commercial fuel cells despite their attractive chemistry.

The Shanghai group’s strategy was to sidestep the trade-off rather than fight it head-on. Instead of pushing sulfonation ever higher, they kept the polymer matrices at moderate sulfonation levels and introduced an inorganic proton conductor, phosphotungstic acid, as a dispersed filler. Phosphotungstic acid belongs to the polyoxometalate family, inorganic clusters with a distinctive Keggin structure in which a central phosphorus atom is caged by twelve tungsten-oxygen octahedra. These clusters are dense with acidic protons and can conduct them efficiently, particularly when hydrated. Crucially, the acid is strong enough to contribute conductivity without requiring the polymer host to be saturated with sulfonic acid groups, which means the membrane can stay dimensionally stable and hydrolytically tough while still moving protons quickly.

Building the composite required care, because polyoxometalates tend to aggregate and can leach out of polymer films. The researchers synthesized a series of sulfonated polyimides with varying degrees of sulfonation and two different chain architectures, random copolymers in which sulfonated units are scattered along the backbone, and block copolymers in which sulfonated and unsulfonated segments are grouped into distinct blocks. Block architectures are known to encourage microphase separation, creating connected hydrophilic channels that can act as proton highways. The phosphotungstic acid was then blended into each matrix using ultrasonic-assisted mixing followed by solution casting, a processing route in which ultrasound helps disperse the inorganic clusters evenly through the polymer solution before it is cast into a film and dried.

Characterization confirmed the approach worked at the molecular level. Fourier-transform infrared spectroscopy detected the vibrational fingerprints of the Keggin clusters inside the composite films, showing that the acid’s characteristic structure survived the blending and casting process intact. Scanning electron microscopy revealed a uniform dispersion of the filler throughout the polymer matrix, with no large aggregates that would have compromised mechanical integrity or created defects. That uniformity matters because proton conduction in a composite depends on connectivity: isolated pockets of conductor do little, but a well-dispersed phase can form continuous pathways that supplement the polymer’s own sulfonic acid network.

The performance data are the heart of the study. Among the many formulations tested, one stood out: a composite built from a block copolymer designated BB (3:1)-s, loaded with ten percent phosphotungstic acid. This membrane achieved a proton conductivity of 0.161 siemens per centimeter, a figure comparable to Nafion 117, the widely used commercial reference material. For a hydrocarbon-based polymer membrane to reach that benchmark is significant, since Nafion’s perfluorinated structure and phase-separated morphology have long given it an edge in hydrated proton transport. Equally important, the conductivity gain came without sacrificing strength: the same membrane recorded a tensile strength of 15 megapascals, indicating that the filler reinforced rather than plasticized the film.

Durability results may prove even more consequential than the conductivity numbers. The optimized composite membrane withstood more than 1,600 hours of hydrolytic stability testing, an endurance figure that addresses the Achilles heel of sulfonated polyimides. Because the membrane does not rely on extreme sulfonation, it absorbs water in a controlled way, limiting the swelling stresses and backbone hydrolysis that normally destroy highly sulfonated films. The authors also report favorable methanol barrier properties, an attribute that matters for direct methanol fuel cells, where fuel crossing the membrane from anode to cathode wastes fuel and poisons the cathode reaction. A membrane that conducts protons well but resists methanol crossover addresses one of the central design tensions in liquid-fuel cell development.

The work fits into a broader international effort to replace or augment perfluorinated ionomers with cheaper, more tunable hydrocarbon membranes. Recent years have seen sulfonated polyimides, polybenzimidazoles, and polyarylene ethers modified with cross-linking, branching, acid-base blending, and a parade of inorganic fillers including graphene oxide, metal-organic frameworks, mesoporous carbon nitride, and various heteropolyacids. Phosphotungstic acid in particular has been anchored into chitosan films, trapped inside metal-organic frameworks, and covalently linked to mesoporous supports in earlier studies. What distinguishes the new report is the systematic pairing of chain architecture with filler loading: by comparing random and block copolymer matrices across a sulfonation series, the researchers could identify a formulation where polymer morphology and inorganic conduction reinforce each other rather than compete.

There remain familiar hurdles between laboratory membranes and fuel cell stacks. Polyoxometalates are water-soluble, and long-term leaching under real operating cycles, with their humidity swings and thermal excursions, will need to be demonstrated beyond the hydrolytic soaking tests reported here. Membrane-electrode assembly integration, chemical stability in the presence of peroxide radicals generated at the electrodes, and manufacturability at scale are all questions the Polymer Bulletin paper does not settle. The authors acknowledge support from the National Natural Science Foundation of China, and the study was conducted at the Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, with co-author Zhai also affiliated with Sushui Energy Technology, a Shanghai company, hinting at an interest in commercial translation.

Still, the result offers a template for how composite design can dissolve a classic trade-off. By letting an inorganic superacid carry part of the proton-transport burden, the polymer matrix can stay modestly sulfonated, and therefore tough and dimensionally stable, while the composite as a whole conducts protons at Nafion-level rates. A membrane that simultaneously delivers 0.161 siemens per centimeter, 15 megapascals of tensile strength, more than 1,600 hours of hydrolytic endurance, and methanol resistance is a rare combination in the hydrocarbon membrane literature. If follow-up work confirms that the phosphotungstic acid stays put over thousands of fuel cell cycles, sulfonated polyimide composites of this kind could move from polymer chemistry journals toward the membranes that actually sit inside hydrogen and methanol fuel cells, where the balance of properties, not any single figure of merit, decides what succeeds.

Subject of Research: Composite proton exchange membranes combining sulfonated polyimide with phosphotungstic acid for fuel cells

Article Title: Sulfonated polyimide/phosphotungstic acid composite proton exchange membranes with balanced properties for fuel cells

Article References: Zhai, F., Zhuang, L., Wei, X., Cao, F., & Zhao, S. (2026). Sulfonated polyimide/phosphotungstic acid composite proton exchange membranes with balanced properties for fuel cells. Polymer Bulletin, 83(12), Article 653. https://doi.org/10.1007/s00289-026-06725-7

Image Credits: AI Generated

DOI: 10.1007/s00289-026-06725-7

Keywords: proton exchange membrane, sulfonated polyimide, phosphotungstic acid, fuel cells, composite membrane, proton conductivity, hydrolytic stability, block copolymer, methanol crossover, Keggin structure, hydrogen fuel, polymer electrolyte

The appeal of solid electrolytes in battery research is easy to understand. Conventional batteries rely on liquid electrolytes—flammable organic solvents that carry ions between the electrodes but also introduce risks of leakage, fire, and chemical degradation. Replacing that liquid with a solid film would make batteries safer, more compact, and potentially compatible with flexible and implantable electronics. The catch is that most solid electrolytes, whether ceramic or polymer based, struggle to move ions as freely as liquids do. Magnesium adds another layer of difficulty: the doubly charged Mg2+ ion interacts strongly with its surroundings, making it notoriously sluggish inside solid frameworks. That is precisely why the conductivity numbers reported in this study turn heads.

The team fabricated their membranes using a straightforward solution casting technique, dissolving Centella asiatica material with magnesium chloride hexahydrate and then adding succinonitrile as a plasticizer. Succinonitrile is an intriguing molecule in its own right—it is a plastic crystal, a solid whose molecules rotate freely in a disordered lattice, and this rotational mobility creates pathways through which ions can hop. When blended into a polymer host, it loosens the rigid structure, suppresses crystallinity, and dramatically increases the fraction of amorphous material where ion transport is fastest. The researchers confirmed these structural changes with a battery of analytical techniques, including scanning electron microscopy with energy-dispersive X-ray analysis, elemental mapping, X-ray diffraction, and X-ray photoelectron spectroscopy.

Those characterization methods told a coherent story. Electron microscopy and elemental mapping showed that the magnesium, chlorine, and nitrogen species were distributed uniformly throughout the membrane, with no signs of the salt agglomeration that plagues poorly formulated polymer electrolytes. X-ray diffraction revealed a dominance of amorphous phases after succinonitrile incorporation—a critical feature, because crystalline regions in a polymer act as barriers that force ions to take long, tortuous detours. X-ray photoelectron spectroscopy verified the chemical interactions between the plant polymer, the magnesium salt, and the plasticizer, confirming that the components were genuinely complexed rather than simply mixed together in a fragile physical blend.

Thermal analysis added further support. Differential scanning calorimetry measured a glass transition temperature of 56.8 degrees Celsius for the plasticized membrane, a reduction that signals enhanced chain mobility in the polymer backbone. Thermogravimetric analysis demonstrated robust thermal stability, meaning the membrane will not decompose under the modest operating temperatures a battery is likely to encounter. This combination of low glass transition temperature and good thermal endurance is the sweet spot that electrolyte designers chase: the polymer chains must wiggle enough to let ions pass, yet the material must hold together over time and temperature without softening into uselessness or breaking down chemically.

The electrical measurements are where the study delivers its headline numbers. Using AC impedance spectroscopy, the researchers measured an ionic conductivity of 1.17 times ten to the minus four siemens per centimeter for the unplasticized membrane. After adding succinonitrile, that figure jumped fifteen-fold to 1.76 times ten to the minus three siemens per centimeter—one of the more respectable values reported for magnesium-ion-conducting biopolymer electrolytes. Temperature-dependent dielectric analysis showed that conduction followed the expected thermally activated behavior, consistent with ions hopping between coordinating sites along the flexible polymer chains. Evans and Wagner polarization measurements were used to determine the transference number, confirming that the current is carried overwhelmingly by ions rather than electrons—an essential property for any electrolyte, since electronic leakage would slowly self-discharge the cell.

Electrochemical stability is often the Achilles heel of biopolymer electrolytes, but here too the results were encouraging. Linear sweep voltammetry established a stability window extending up to 2.74 volts, wide enough to support practical magnesium battery chemistries. Cyclic voltammetry demonstrated high reversibility over 150 cycles, indicating that the electrode processes at the membrane interface could proceed repeatedly without severe degradation or passivation. For a material derived from a medicinal plant, sustaining 150 reversible electrochemical cycles is a meaningful benchmark, suggesting the membrane interface remains chemically compatible with the electrode materials over extended operation.

The proof, of course, lies in an actual device. The team assembled primary magnesium-ion batteries using their highest-conductivity plasticized membrane as the electrolyte separator, paired with two different cathode materials. With molybdenum disulfide as the cathode, the cell delivered an open-circuit voltage of 1.96 volts; with manganese dioxide, it delivered 1.91 volts under load testing. Both values are consistent with the thermodynamics of magnesium-based primary cells and demonstrate that the biomaterial electrolyte is not merely a laboratory curiosity that performs well in isolation—it can function as the working heart of a complete electrochemical cell.

The choice of Centella asiatica as the polymer host deserves attention. The plant is rich in polysaccharides and other oxygen-bearing functional groups that can coordinate magnesium ions and provide the hopping sites needed for conduction. It is also abundant, inexpensive, and biodegradable, which aligns with a growing movement in materials science toward sustainable, environmentally benign battery components. Previous work from the same research group and others has explored biopolymer electrolytes derived from cellulose acetate, pectin, gellan gum, agar, tamarind seed polysaccharide, sodium alginate, and even corn silk extract, building a body of evidence that natural polymers can serve as credible hosts for ion-conducting membranes. This study extends that lineage by showing that Centella asiatica, when properly complexed with a magnesium salt and plasticized with succinonitrile, can reach conductivities at the upper end of the biopolymer electrolyte spectrum.

There are, naturally, caveats. These are primary batteries, not rechargeable ones, and magnesium’s tendency to form passivating layers on metal anodes remains a formidable obstacle to rechargeable magnesium technology. The 2.74-volt stability window, while adequate for the demonstrated cells, would need to widen considerably for high-voltage applications. And scaling from laboratory-cast films to industrially manufactured membranes always presents challenges in reproducibility and mechanical consistency. Still, the study offers a compelling demonstration that the path to safer, greener batteries may run through unexpected territory. A plant prized for centuries in traditional healing now helps shuttle charged atoms through a solid film—and in doing so, it lights up a small but promising corner of the future of energy storage.

Subject of Research: Succinonitrile-plasticized Centella asiatica-based solid biomaterial electrolytes for primary magnesium batteries

Article Title: Succinonitrile-plasticized centella asiatica-based solid biomaterial electrolytes for primary magnesium batteries

Article References: Begam, M. M., Chandra, M. L., & Selvasekarapandian, S. (2026). Succinonitrile-plasticized centella asiatica-based solid biomaterial electrolytes for primary magnesium batteries. Ionics. https://doi.org/10.1007/s11581-026-07538-4

Image Credits: AI Generated

DOI: 10.1007/s11581-026-07538-4

Keywords: solid electrolyte, biomaterial, Centella asiatica, magnesium battery, succinonitrile, ionic conductivity, polymer electrolyte, MgCl2, primary battery, biodegradable materials, electrochemistry, energy storage