Thermal energy storage via PCMs is a linchpin technology for harnessing renewable sources and capturing waste heat, crucial for decarbonizing energy systems. However, while materials with substantial melting enthalpies can hold large amounts of energy, their intrinsic low ability to conduct heat restricts the speed at which they can be charged or discharged. Previous efforts to circumvent this challenge involved creating composite PCMs—blending traditional PCMs with thermally conductive additives—or using external forces to enhance melting contact, both of which carry penalties such as a decrease in energy storage capacity or additional power costs.

The latest work, detailed in a publication appearing on January 8, 2026, in Nature, introduces an innovative composite coating design for sealed phase-change thermal batteries. This design exploits a dual-function approach combining a pulse-heated (PH) layer with a lubricious slip surface, enabling a phenomenon the authors term slip-enhanced close-contact melting (sCCM). In this mode, the pulse-heated layer initiates premelting of the PCM, establishing immediate close contact between solid and liquid phases and thus jumping over the typical bottlenecks of heat transfer.

What sets this approach apart is how the slip surface facilitates the seamless sinking of the remaining solid PCM during charging, effectively maintaining unimpeded movement and continuous contact with the heated surface. This dynamic coordination ensures the melting fronts progress quickly and efficiently, translating into unprecedented charging rates. The researchers demonstrated a record-breaking power density exceeding 1,100 kW per cubic meter with organic PCM prototypes, a quantum leap relative to previous benchmarks.

The strategy is underpinned by a robust theoretical model elucidating how the slip surface mechanically and thermally supports rapid phase transformation. According to this model, the absence of frictional resistance allows the solid PCM to settle without disrupting thermal contact, which would otherwise degrade performance due to trapped air gaps or uneven melting. This insight offers a powerful design principle for a new generation of thermal batteries where energy density and fast charging are no longer mutually exclusive.

Moreover, the solution is engineered to function within sealed systems, ensuring practical integration with existing thermal energy storage infrastructures. By eliminating the need for imposed external pressure or bulky thermal conductivity enhancers, energy losses and supplementary operational complexities are minimized. This streamlines factory production, installation, and maintenance cycles, thereby improving the technology’s commercial viability and environmental footprint.

The research further highlights the versatility and scalability of the composite coating, showing it can adapt to various PCM chemistries encompassing a wide temperature spectrum. This broad applicability positions the technology not only for stationary renewable applications but also for industrial waste heat recovery, electric vehicle thermal management, and even aerospace thermal regulation, where fast and efficient heat storage and release are paramount.

Crucially, extended cycling tests indicate impressive durability and sustained performance across hundreds of thermal charge-discharge cycles. This resilience addresses a critical barrier to commercialization, where material degradation and performance fading tend to limit long-term reliability. The composite’s design inherently mitigates mechanical stresses and phase separation issues, ensuring consistent thermal characteristics over the device’s lifetime.

Future investigations promise to refine this technology further, potentially incorporating adaptive control systems that optimize pulse heating profiles dynamically based on real-time thermal demand patterns. Integration with smart grid infrastructure could elevate phase-change thermal batteries from mere energy storage units to active participants in energy balancing and peak load shaving, vastly augmenting grid resilience and efficiency.

The paradigm introduced by this research propels phase-change thermal batteries into a new era, overcoming a longstanding dichotomy between energy density and charging speed. By exploiting the physics of slip and close-contact melting synergistically, the work brings high-performance, scalable, and energy-efficient thermal storage within tangible reach. As the world races toward carbon neutrality, such innovations form the backbone of sustainable, resilient, and cost-effective energy systems.

In summary, this pulse heating and slip-layered coating concept not only surmounts critical limitations but also opens the door to high power densities previously deemed unachievable in organic PCM systems. The theoretical insights paired with empirical validation represent a significant leap forward, with exciting implications across multiple sectors reliant on thermal management and renewable energy conversion. Its publication signals a milestone in energy storage science and a beacon for future interdisciplinary research and commercial development.

Subject of Research: Enhancement of phase-change thermal battery charging rates through composite coating design enabling slip-enhanced close-contact melting (sCCM).

Article Title: Pulse heating and slip enhance charging of phase-change thermal batteries.

Article References:
Li, ZR., Hu, N., Wang, ZB. et al. Pulse heating and slip enhance charging of phase-change thermal batteries. Nature 649, 360–365 (2026). https://doi.org/10.1038/s41586-025-09877-0

Image Credits: AI Generated

DOI: 10.1038/s41586-025-09877-0

Keywords: Phase-change materials, thermal battery, energy storage, charging rate, pulse heating, slip-enhanced close-contact melting, composite coating, renewable energy, waste heat recovery, power density.

Hydrogen, as a clean fuel, holds tremendous promise for decarbonizing energy systems and powering next-generation vehicles. However, its storage has been plagued by fundamental difficulties. Conventional storage methods demand cryogenic temperatures near -253 °C or extreme pressures exceeding 350 bar, imposing significant safety, economic, and logistical challenges. Solid-state storage in metal hydrides, particularly magnesium hydride (MgH₂), presents an alluring alternative due to its high theoretical hydrogen capacity. Yet, harnessing this material in practical devices has been hindered by the necessity to operate at temperatures above 300 °C, which is energy-intensive and mechanically taxing over time.

The team at Science Tokyo has ingeniously integrated MgH₂ into a battery-like cell architecture, utilizing a newly developed solid electrolyte with the formula Ba₀.₅Ca₀.₃₅Na₀.₁₅H₁.₈₅. This electrolyte exhibits superionic conduction of hydride ions through an anti-α-AgI-type crystal lattice—a structure that facilitates rapid H⁻ ion mobility via face-sharing tetrahedral and octahedral sites. Remarkably, the material demonstrates significant ionic conductivity at room temperature (2.1 × 10⁻⁵ S cm⁻¹) and maintains electrochemical stability throughout repeated cycling. Such attributes enable the battery to shuttle hydride ions efficiently between the electrodes at temperatures far below those previously deemed necessary.

Operationally, the MgH₂ functions as the anode where, during charging, it releases hydride ions that travel through the solid electrolyte to the cathode, comprised of hydrogen gas. Here, the hydride ions are oxidized, liberating molecular hydrogen. During discharge, the process reverses as hydrogen gas at the cathode is reduced back to hydride ions, which migrate through the electrolyte to react with magnesium metal at the anode, reforming MgH₂. This reversible electrochemical mechanism effectively stores and releases hydrogen fuel on demand, all within a thermally manageable regime under 100 °C.

Empirical evaluations reveal that this solid-state hydrogen battery achieves the full theoretical capacity of MgH₂, approximately 2,030 mAh g⁻¹, equating to 7.6 weight percent hydrogen storage. This performance surpasses earlier electrochemical attempts hampered by poor ion transport and limited reversibility, laying a foundation for durable, high-capacity hydrogen storage solutions. The battery’s ability to undergo repeated charge-discharge cycles without significant capacity degradation highlights its robustness and application potential.

Prior approaches to magnesium hydride hydrogen storage involved thermal absorption and desorption at elevated temperatures ranging from 300 to 400 °C. These methods were inherently inefficient due to their high energy cost and slow kinetics, along with undesirable side reactions that compromised longevity. Alternatively, electrochemical storage employing liquid electrolytes at lower temperatures was limited by insufficient hydrogen-ion mobility, precluding attainment of theoretical storage limits. The innovation from Science Tokyo’s researchers circumvents these issues by integrating a solid electrolyte that combines high ionic conductivity with chemical stability and compatibility with magnesium hydride.

Dr. Takashi Hirose, along with colleagues Assistant Professor Naoki Matsui and Institute Professor Ryoji Kanno, spearheaded this research within the Research Center for All-Solid-State Battery. Their work, slated for publication in Science on September 18, 2025, marks a pivotal step toward practical hydrogen energy systems. The team’s success in lowering operational temperature while maintaining capacity and reversibility challenges long-held assumptions regarding the trade-off between temperature and storage performance.

One of the notable technical details of this electrolyte lies in its carefully engineered composition, where barium, calcium, and sodium ions occupy body-centered lattice positions, creating conducive pathways for hydride ion migration. This strategic incorporation of multiple cations tunes the crystalline environment to optimize ionic transport properties. The superionic conduction facilitated by this anti-α-AgI-type lattice is a rare achievement in solid electrolytes designed for hydrogen ion transport, making it a cornerstone of the battery’s operation.

From an application standpoint, this hydrogen battery could revolutionize energy carriers for a wide array of industries. Presently, the challenges of hydrogen storage limit the feasibility of hydrogen-powered vehicles and impede the broader adoption of hydrogen fuel cells. The ability to store substantial amounts of hydrogen safely at low temperatures and moderate pressures opens pathways to integrate hydrogen energy more seamlessly into transportation, stationary power generation, and grid storage. Moreover, the elimination of hazardous liquid electrolytes and reliance on solid-state materials enhances the device’s safety profile.

This development aligns with broader global efforts to transition to sustainable energy systems. Hydrogen, when produced via renewable sources, offers a zero-emission fuel that can decarbonize sectors that are otherwise difficult to electrify. By overcoming storage obstacles, the newly developed hydrogen battery could accelerate the realization of hydrogen’s potential, reducing dependency on fossil fuels and helping mitigate climate change effects.

The successful demonstration of hydride ion conduction in a solid electrolyte also has implications beyond hydrogen storage. It could inspire new research directions in the design of solid-state ionic conductors for other energy conversion and storage technologies. Solid-state batteries with similar ionic transport mechanisms might exhibit improved stability, energy density, and safety compared to current lithium-ion technologies.

Despite this leap forward, the path to commercialization will require further validation including scale-up, integration with real-world systems, and long-term durability testing under varied environmental conditions. However, the promising laboratory results provide a strong foundation for continued development. Collaborative efforts between industry and academia could expedite the transition from prototype devices to market-ready technologies.

In summary, the Institute of Science Tokyo’s solid-state hydrogen battery represents a significant advance in clean energy technology. By achieving high-capacity, reversible hydrogen storage at a remarkably low operating temperature using a novel hydride ion-conducting electrolyte, it overcomes key limitations that have stalled hydrogen’s widespread adoption. This innovation not only paves the way for safe and practical hydrogen storage but also energizes the broader hydrogen economy, potentially igniting a transformative shift in how we produce, store, and utilize clean energy in the coming decades.

Subject of Research:
Not applicable

Article Title:
High-Capacity, Reversible Hydrogen Storage Using H⁻-Conducting Solid Electrolytes

News Publication Date:
18-Sep-2025

Web References:
http://dx.doi.org/10.1126/science.adw1996

Image Credits:
Institute of Science Tokyo (Science Tokyo)

Keywords

Hydrogen storage, Chemical engineering, Physical sciences, Conductivity, Environmental sciences, Applied sciences and engineering

During the hydrogen production process, traditional methods typically rely on fossil fuels, emitting significant quantities of carbon dioxide. However, the study emphasizes that hydrogen does not necessarily have to emerge from synthetic production methods. Instead, geological processes occurring deep within the Earth present viable alternatives for generating this essential gas, ultimately paving the way for a cleaner and greener future. The discovery emphasizes that hydrogen generation can occur naturally through geological phenomena, thereby reducing reliance on energy-intensive synthetic processes.

Through the innovative application of numerical plate tectonic simulations, the research team has established a correlation between specific geological features and significant hydrogen production potential. Their findings indicate that mountain ranges, particularly those known to feature deep mantle rocks, are prime locations for hydrogen accumulation. Such environments not only favor the geological processes conducive to hydrogen generation, but they also provide natural reservoirs where the gas can be stored and ultimately extracted for energy purposes. This opens a new frontier in exploring natural hydrogen sources.

The researchers elucidate a phenomenon called serpentinization, where mantle rocks undergo transformation in the presence of water, resulting in the formation of new minerals along with the release of hydrogen gas. This process typically requires the mantle rocks to be brought closer to the Earth’s surface, a scenario that is more likely to occur in mountain ranges due to tectonic activity. Consequently, the research team has postulated that regions with such geological formations may harbor extensive reservoirs of natural hydrogen awaiting exploration.

Dr. Zwaan and his colleagues have meticulously analyzed how tectonic environments evolve over millennia. Their simulations indicate these mountainous areas, often subjected to significant geological upheaval from tectonic forces, are optimal for both the generation and retention of hydrogen. Research suggests that conditions within mountain ranges foster the exhumation of mantle rocks at temperatures between 200-350°C, striking the perfect balance for effective serpentinization to occur.

The implications of this research extend far and wide, suggesting that specific mountain ranges across Europe—such as the Pyrenees, the Alps, and the Balkans—may be ripe for exploration, where previous studies have hinted at the presence of naturally occurring hydrogen. The findings act as a clarion call for energy companies and researchers alike to intensify their efforts in searching these geological areas for natural hydrogen reservoirs, cointegrating energy generation with sustainable practices in the age of climate action.

This emerging narrative of natural hydrogen as a viable energy source represents an evolution in our understanding of energy generation, linking complex geological activities with tangible environmental benefits. The exploration of these resources could lead to a significant reduction in carbon footprints associated with hydrogen production. By harnessing the potential of geological processes that have been titled as inefficient or overlooked, scientists and engineers are on the verge of creating a renewable energy paradigm grounded in the very formation of our planet.

However, as exciting as these findings may appear, they are just the beginning. The study calls for innovative concepts and exploration strategies to identify locations with the highest potential for economically viable hydrogen accumulation. As the configurations of the Earth’s crust continue to intrigue and challenge our perceptions of energy resources, it is clear that interdisciplinary collaboration will be paramount. Insights drawn from geological, geodynamic, and energy sciences will need to fuse in novel ways to realize the promise of natural hydrogen.

Furthermore, the study underscores the importance of understanding the tectonic history of exploration sites, coupled with identifying the timing of geological processes. Hydrogen reservoirs will not form randomly; rather, they must follow specific geological timelines that include formative rifting events before mountain building can occur. This knowledge is crucial since it informs researchers where to target their efforts in the quest for natural hydrogen and can significantly enhance the efficiency of exploration missions.

The viability of natural hydrogen generation will eventually depend on vast exploration efforts as proposed by the research team. Beyond the scope of hydrogen production, the study opens pathways to uncover how migrating hydrogen interacts with microbial ecosystems deep within the Earth. These ecosystems could provide even richer insights into the formation and maintenance of hydrogen reservoirs, assisting in the overall understanding of natural resource cycling, migration pathways, and the interactions within subsurface environments.

In conclusion, the breakthrough research enables us to rethink our approach to hydrogen production by revealing the vast potential hidden in the world’s mountain ranges. As scientists gear up to explore and validate these findings, we may be witnessing the dawn of a natural hydrogen industry that could significantly transform our energy landscape. The possibility of utilizing naturally generated hydrogen from geological processes not only underscores our planet’s complexity but also aligns with the pressing need for cleaner energy solutions in combating climate change.

Subject of Research:
Article Title: Rift-inversion orogens are potential hotspots for natural H2 generation.
News Publication Date: 19-Feb-2025
Web References:
References:
Image Credits: Credit: Frank Zwaan, GFZ

Keywords: Hydrogen, Sustainable Energy, Natural Resources, Geological Sciences, Climate Change, Tectonic Models, Serpentinization, Energy Transition.