The study, published in the journal Ionics by Zhanshou Yang, Fa-Feng Xu, and colleagues at the Qinghai Institute of Salt Lakes of the Chinese Academy of Sciences, centers on a process called dealloying. In dealloying, one element is selectively dissolved out of an alloy, leaving behind a sponge-like scaffold of the remaining element riddled with pores at the nanometer scale. The technique has a pedigree in materials science, having been used to create nanoporous gold and other architectures, and it has increasingly attracted attention as a scalable way to fabricate porous electrode materials for rechargeable batteries. Applied to silicon-bearing alloys, it produces porous silicon structures whose internal voids act as built-in expansion chambers.

That architectural trick addresses the core failure mode of silicon anodes. In a dense silicon particle, the volume change that accompanies lithiation generates enormous mechanical stress. Particles pulverize, fresh surfaces are repeatedly exposed to the electrolyte, and a thick, unstable solid electrolyte interphase layer grows and rebuilds with every cycle, consuming lithium and raising the cell’s internal resistance. A porous particle, by contrast, can expand into its own empty space. The pores absorb much of the strain, the particle’s outer dimensions stay comparatively stable, and the electrode’s conductive network and binder matrix survive far longer.

Porosity alone, however, does not solve every problem. Silicon is a semiconductor with modest intrinsic conductivity, and the tortuous pathways through a porous structure can slow both electrons and lithium ions. The Qinghai team therefore wrapped the porous silicon in a carbon coating, producing a composite they designate Si@C. The carbon shell serves a dual role: it provides an electron-conducting highway that connects the silicon to the current collector, and it acts as a mechanical and chemical skin that stabilizes the electrode structure and limits parasitic reactions with the electrolyte. Carbon coatings of this kind have become a standard strategy in silicon anode research, but their effectiveness depends heavily on the quality of the underlying silicon architecture and on how the composite is formulated.

The second half of the team’s strategy is arguably the more pragmatic one: blending the carbon-coated porous silicon with graphite. Graphite remains the workhorse anode of the lithium-ion industry, prized for its low cost, flat voltage profile, and remarkable structural stability over thousands of cycles. By mixing silicon with graphite, researchers can trade some of silicon’s enormous capacity for graphite’s reliability, while the graphite matrix helps buffer swelling and maintains electronic contact throughout the electrode. The ratio matters enormously. Too little silicon and the energy-density gain is marginal; too much and the electrode’s mechanical integrity collapses within a few hundred cycles.

Yang and colleagues systematically optimized this ratio, testing different proportions of porous silicon to graphite before settling on a mass ratio of 1:2. At that composition, the composite delivered the best combination of capacity, stability, and rate performance in their experiments. The finding underscores a broader lesson in battery engineering: the performance of a composite electrode is not simply the weighted average of its components, but emerges from how those components interact mechanically and electrochemically during cycling. The graphite appears to function not merely as a diluent but as an active structural partner for the swelling silicon.

The electrochemical results reported in the paper are striking. After 500 charge-discharge cycles, the optimized Si@C anode retained a reversible capacity of 688.5 milliampere-hours per gram, corresponding to a capacity retention of 63.6 percent. For context, conventional graphite anodes typically deliver around 350 to 370 milliampere-hours per gram, so even after substantial degradation the composite still stores nearly twice as much charge per unit mass. Equally important is the coulombic efficiency, which the team reports at 99.9 percent. This figure measures how many lithium ions that enter the anode during charging come back out during discharge, and values approaching 100 percent indicate that parasitic side reactions, which slowly poison a cell, have been largely suppressed.

The authors state that these results surpass previously reported data for comparable silicon-based anodes in both cycling stability and rate performance, the latter describing the electrode’s ability to deliver capacity at high charging speeds. Rate capability is often the quiet casualty of silicon anode designs, because the same structural features that buffer swelling can impede ion transport. The combination of porous silicon, a conductive carbon coating, and a graphite matrix appears to keep those transport pathways open even as the electrode ages, allowing the material to sustain fast charging without catastrophic capacity loss.

The work also carries a regional and industrial dimension. The Qinghai Institute of Salt Lakes specializes in the chemistry and utilization of China’s salt lake resources, and the study was supported by provincial programs including the Kunlun Talents-Top Talents project and an applied basic research grant from Qinghai Province. Silicon anode research worldwide is driven by the same calculus: electric vehicles demand longer driving ranges, and grid storage demands cheaper, denser cells. Every incremental improvement in silicon anode longevity translates into smaller, lighter, or longer-lived batteries, which is why the field has produced a torrent of strategies, from nanowires and core-shell structures to engineered binders and electrolyte additives, all aimed at taming silicon’s expansion.

What distinguishes the present approach is its relative simplicity. Dealloying is a wet-chemical or electrochemical process that can, in principle, be scaled to produce large quantities of porous material, and blending with graphite requires no exotic equipment. The authors suggest that the synergy between the pore-buffered silicon and the carbon coating, reinforced by the graphite framework, offers a design template for future high-performance silicon-based anodes. Challenges remain before such materials reach commercial cells, including the first-cycle losses that typically accompany silicon’s large surface area and the cost of processing, but the demonstration that a 1:2 silicon-to-graphite blend can survive 500 cycles with near-perfect coulombic efficiency marks a meaningful step. As the demand for energy-dense, long-lasting lithium-ion batteries continues to climb, strategies that combine clever materials architecture with industrial pragmatism are likely to define the next generation of anode chemistry.

Subject of Research: Dealloying-derived porous silicon-carbon composite anodes for high-stability lithium-ion batteries

Article Title: Dealloying-derived porous Si@C anode with optimized graphite integration for high-cycling-stability lithium-ion batteries

Article References: Yang, Z., Xu, F.-F., Niu, Z., Feng, H., Yang, K., & Zeng, J. (2026). Dealloying-derived porous Si@C anode with optimized graphite integration for high-cycling-stability lithium-ion batteries. Ionics. https://doi.org/10.1007/s11581-026-07515-x

Image Credits: AI Generated

DOI: 10.1007/s11581-026-07515-x

Keywords: lithium-ion batteries, silicon anode, dealloying, porous silicon, carbon coating, graphite, cycling stability, coulombic efficiency, energy density, anode materials, electrochemistry, battery technology

The motivation for the work lies in the well-known weaknesses of enzyme-based glucose sensors, which dominate the commercial market but degrade when exposed to fluctuations in pH, temperature, or humidity. Enzymes are fragile biological molecules, and their activity drifts over time, complicating long-term monitoring. Nonenzymatic sensors replace the enzyme with an inorganic catalyst, trading some biochemical specificity for dramatically improved stability and shelf life. Among inorganic catalysts, nickel-based materials have long been favored because they are cheap, abundant, and highly active toward glucose oxidation in alkaline media, but their performance depends critically on how much catalytic surface area can be packed onto an electrode.

The Iranian team, led by Mohadeseh Haghkhah and Rahim Mohammad-Rezaei, addressed that surface-area problem with a two-step electrochemical strategy. First, they electrodeposited a nickel-copper alloy onto a flat graphitic electrode that had been coated with a composite of acid-treated carbon nanofibers and sulfur-nitrogen co-doped graphene quantum dots. The deposition was performed at minus 0.9 volts for 120 seconds in a solution containing nickel chloride, copper chloride, and boric acid. Then came the crucial dealloying step: applying a positive potential of 0.2 volts for 180 seconds selectively dissolves copper from the alloy while nickel, which rapidly forms a protective passive oxide layer, stays behind.

The choice of dealloying potential proved decisive. At 0.1 volts, substantial copper remained on the surface, confirmed by residual copper redox peaks in cyclic voltammetry. At 0.5 volts, the process became too aggressive and significant nickel leached away alongside the copper. Energy-dispersive X-ray spectroscopy and amperometric current-time traces both pointed to 0.2 volts as the sweet spot, where copper removal was nearly complete while nickel loss was minimized. Scanning electron microscopy revealed the dramatic morphological consequence: the spherical NiCu nanoparticles collapsed into needle-like nickel structures with vastly increased electroactive surface area, a transformation that simply did not occur when the dealloying step was skipped.

The underlying scaffold is just as important as the nanoneedles themselves. Carbon nanofibers, roughly 60 to 100 nanometers in diameter, were activated with a sulfuric and nitric acid treatment that replaced surface-bound oxides with hydroxyl groups, boosting hydrophilicity. The graphene quantum dots, synthesized hydrothermally from citric acid and thiourea, were confirmed by infrared spectroscopy and fluorescence measurements, showing characteristic blue emission at 443 nanometers. Raman spectroscopy tracked the whole transformation: copper oxide vibrational bands visible in the alloyed electrode vanished almost entirely after dealloying, while bands associated with nickel oxyhydroxide and hydroxide phases emerged, providing direct spectroscopic evidence that the copper had been stripped and the nickel converted to its active form.

Electrochemical impedance spectroscopy quantified the synergy between the components. The charge-transfer resistance of the full composite shrank progressively as carbon nanofibers and then quantum dots were added, and dropped again after copper removal. Cyclic voltammetry showed quasi-reversible nickel(II)/nickel(III) redox peaks at approximately 0.29 and 0.5 volts, and the electroactive surface area, calculated by charge integration, told a striking story: 0.146 square centimeters for nanoneedles on bare graphite, 2.49 square centimeters with carbon nanofibers, and 6.00 square centimeters with the full carbon nanofiber-quantum dot composite. In other words, the nanostructured scaffold multiplied the effective catalytic area more than fortyfold relative to the plain electrode.

Glucose oxidation on the finished electrode follows a well-understood electrochemical-chemical mechanism. In the anodic scan, surface nickel hydroxide is electrochemically oxidized to nickel oxyhydroxide, the true catalytic species. Glucose then reduces nickel oxyhydroxide back to nickel hydroxide while being converted to gluconolactone, and the regenerated nickel hydroxide is oxidized again, sustaining a continuous catalytic cycle that amplifies the anodic current. Scan-rate studies confirmed that peak currents scaled linearly with scan rate, consistent with this surface-confined redox cycle. Crucially, the un-dealloyed NiCu electrode showed essentially no sensitivity to glucose, demonstrating that residual copper participates in parasitic side reactions and disrupts the nickel redox kinetics that the sensing mechanism depends on.

The analytical figures of merit are impressive. Operating at 0.40 volts in 0.1 molar potassium hydroxide, the optimized sensor achieved a sensitivity of 2105.95 microamperes per millimolar per square centimeter, a linear range spanning 0.012 to 12 millimolar, and a detection limit of 3.13 micromolar, with a response time of about five seconds. That sensitivity represents a 240 percent improvement over electrodes lacking either the quantum dots or the dealloying treatment, and it compares favorably with recently reported nickel-based nonenzymatic sensors built on MoS2, MXenes, and layered double hydroxides. Selectivity tests showed that physiologically relevant concentrations of ascorbic acid, dopamine, citric acid, uric acid, and sodium chloride produced negligible signal changes, with interference fluctuations staying below five percent.

Reliability testing reinforced the platform’s practical credentials. Three independently fabricated electrodes gave responses with a relative standard deviation of just 3.5 percent, and repeated measurements on a single electrode yielded 4.15 percent. The amperometric signal remained stable for more than 1500 seconds of continuous operation, and the electrode retained its performance over four weeks of storage with only 3.19 percent variation. In real-world validation, the team deproteinized human serum with acetonitrile, added just 15 microliters of the treated serum to the micro-drop cell, and measured a glucose concentration of 4.90 millimolar using the standard addition method, with spike recoveries between 97.22 and 102.82 percent. Commercial glucometers read the same samples at 5.01 millimolar, a statistically indistinguishable result.

The micro-drop platform itself may prove as consequential as the nanomaterials. Built from air-dry modeling clay, epoxy resin, and flat graphitic electrodes arranged radially around a well of at most 800 microliters, it is inexpensive, reusable, and ideally suited to clinical samples where volume is scarce. Unlike disposable screen-printed electrodes, the flat platform can be regenerated and monitored over the long term. The authors suggest the combination of low cost, straightforward fabrication, micro-volume capability, and serum-level accuracy positions the sensor for point-of-care diagnostics and sample-limited biomedical assays, offering a glimpse of how rational nanoscale engineering, in this case the simple act of etching copper out of an alloy, can translate into clinically meaningful analytical performance.

Subject of Research: Nonenzymatic electrochemical glucose sensing using alloying-dealloying activated NiOOH nanoneedles on carbon nanofiber-graphene quantum dot composites

Article Title: Electrochemical alloying-dealloying driven activation of NiOOH nanoneedles on carbon nanofiber-graphene quantum dot composites for nonenzymatic glucose sensing on a micro-drop flat platform

Article References: Electrochemical alloying-dealloying driven activation of NiOOH nanoneedles on carbon nanofiber-graphene quantum dot composites for nonenzymatic glucose sensing on a micro-drop flat platform. (n.d.). https://doi.org/10.1016/j.rechem.2026.103905

Image Credits: AI Generated

DOI: 10.1016/j.rechem.2026.103905

Keywords: glucose sensor, nonenzymatic sensing, NiOOH nanoneedles, dealloying, carbon nanofibers, graphene quantum dots, electrodeposition, micro-drop electrode, electrocatalysis, human serum, point-of-care diagnostics, electrochemical biosensor