Lithium-metal batteries have long tantalized researchers with the promise of far greater energy density than conventional lithium-ion cells. The catch: needle-like dendrites grow on the lithium surface during charging, puncturing separators, draining capacity, and sometimes triggering fires. Two peer-reviewed studies offer evidence that quasi-solid electrolytes can push Coulombic efficiency past 99.9% and keep pouch cells running through extreme heat and physical damage. The first, led by corresponding author Rui Wen of the Chinese Academy of Sciences, appeared in Nature Communications in 2022. The second, with corresponding author Xin Fan of Zhejiang University, was published in the same journal in 2025. As of spring 2026, if those numbers hold up under independent testing, the timeline for next-generation batteries in electric vehicles and grid storage could shorten considerably.
What the research actually shows
The two Nature Communications papers attack different pieces of the lithium-metal problem, and a supporting review in Nano-Micro Letters (published in 2024) places both within a broader wave of quasi-solid electrolyte research. It is worth noting that the Nano-Micro Letters article is a secondary source that aggregates and surveys others’ work; it does not independently validate the experimental claims of the other two papers.
The earlier study, published in 2022, built NCM811//Li pouch cells using a metal-organic framework (MOF)-based quasi-solid electrolyte. MOFs are porous crystalline materials whose tiny, uniform channels can guide lithium ions while physically blocking the dendrites that plague liquid-electrolyte cells. In testing, these pouch cells were cycled at temperatures reaching 90 degrees Celsius and retained substantial capacity after extended use. More striking, the cells kept working after being bent and cut, a direct simulation of the kind of abuse a battery might face in a vehicle crash. Conventional liquid electrolytes are flammable and prone to thermal runaway under similar stress, so a quasi-solid alternative that survives both heat and puncture addresses two of the most persistent safety concerns in lithium-metal chemistry.
The second paper, published roughly three years later in 2025, zeroes in on Coulombic efficiency, the ratio of charge you can pull out of a battery to the charge you put in. In lithium-metal systems, even tiny efficiency losses compound over hundreds of cycles, steadily eating away at usable capacity. The researchers engineered a super-saturated electrolyte with a compressed solvation structure and reported pushing lithium-metal electrodes beyond 99.9% Coulombic efficiency at the pouch-cell level, a format far closer to commercial relevance than the coin cells often used in early-stage research.
The Nano-Micro Letters review, published by Springer Nature in 2024, surveys the tradeoff between ionic conductivity and safety across quasi-solid and gel electrolytes and catalogs multi-thousand-cycle demonstrations in several alkali-metal battery systems. That broader survey confirms the MOF-based and super-saturated approaches are part of a wider research push, not isolated outliers. However, because it is a review rather than an original experimental study, it should not be read as independent proof of the other two papers’ specific performance claims.
Where the 99.98% figure stands
The headline figure of 99.98% Coulombic efficiency has circulated in coverage of these advances, but the peer-reviewed paper that most directly addresses efficiency quantifies its achievement as exceeding 99.9%. Whether a specific cell configuration hit 99.98% under particular test conditions has not been independently confirmed by a second primary source. That distinction matters: at these levels, each hundredth of a percent translates into meaningful differences in how many cycles a battery can survive before its capacity drops below a useful threshold. Readers should treat the 99.98% number as plausible but unconfirmed until additional replication data or third-party testing results appear.
What remains uncertain as of spring 2026
Cycle-life claims carry their own caveats. The Nano-Micro Letters review references multi-thousand-cycle results, but those numbers span different chemistries, cell formats, and test protocols. Translating lab-scale cycling data into real-world product warranties requires accounting for calendar aging, temperature swings, and manufacturing tolerances that small-batch pouch cells do not fully capture.
None of the three studies includes a cost analysis or commercial scalability assessment. MOF synthesis, super-saturated electrolyte preparation, and gel-electrolyte integration each add processing steps that could raise manufacturing costs relative to established liquid-electrolyte production lines. Without published data on material costs per kilowatt-hour or yield rates at scale, there is no reliable way to estimate when these chemistries might compete on price with existing lithium-ion cells.
Battery manufacturers have not publicly tied integration timelines to these specific studies. Companies such as Toyota, Samsung SDI, and QuantumScape have announced their own solid-state programs, but those efforts use different electrolyte architectures and face their own scaling hurdles. Drawing a direct line from the Nature Communications results to a production vehicle battery would overstate the evidence.
Environmental testing also has gaps. The MOF-based pouch cells survived 90-degree-Celsius cycling, but no published data from these studies addresses performance under variable humidity, sub-zero temperatures, or the vibration profiles typical of automotive use. Dendrite suppression that works in a controlled lab may behave differently across a decade of real-world driving.
How quasi-solid compares to fully solid-state efforts
Readers following the battery space may wonder how quasi-solid electrolytes differ from the fully solid-state cells that companies like Toyota have targeted for production later this decade. Fully solid electrolytes, typically ceramics or sulfides, eliminate liquid components entirely but struggle with poor contact at electrode interfaces and brittleness under mechanical stress. Quasi-solid and gel electrolytes retain a small amount of liquid or polymer phase, which improves ion transport and flexibility at the cost of slightly lower theoretical safety margins. The Nature Communications results suggest that this compromise may be more practical in the near term: the MOF-based cells demonstrated mechanical resilience that many rigid ceramic electrolytes cannot yet match.
What independent replication would need to show
All three core sources are peer-reviewed journal articles, placing them near the top of the evidence hierarchy for scientific claims. The two Nature Communications papers report original experimental data from pouch cells, not just theoretical modeling, which makes their findings more relevant to eventual product development. Still, there is a wide gap between a successful pouch cell in a university lab and a battery pack bolted under a production car.
The clearest next milestone is independent replication. If other research groups reproduce these efficiency and cycle-life numbers using standardized test protocols and larger-format cells, confidence in the results will grow substantially. It will also matter how quasi-solid systems perform when paired with high-voltage, high-loading cathode designs that more closely resemble commercial cells.
Regulators and safety bodies will focus on abuse testing at the module and pack level. The MOF-based electrolyte’s ability to withstand high temperatures and mechanical damage is encouraging, but automotive and grid-storage approval typically requires extensive nail penetration, crush, overcharge, and thermal runaway testing far beyond what these studies cover. Until that system-level data exists, claims about fundamentally safer lithium-metal packs remain promising but provisional.
For anyone tracking the electric vehicle supply chain or grid storage market as of spring 2026, the research narrows the gap between lithium-metal’s theoretical promise and its practical viability. Quasi-solid electrolytes are solving real problems, and the results are appearing in high-quality journals with pouch-cell data rather than only small-format experiments. The barriers that have stalled lithium-metal batteries for years (dendrite growth, low efficiency, and flammability) are being chipped away in concrete, measurable ways. But every step from lab cell to mass production introduces constraints the current data do not yet address, and no source in the published research provides a credible timeline for closing that gap.
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*This article was researched with the help of AI, with human editors creating the final content.
