Solid Electrolytes Keep Batteries Running at Minus 60 Degrees, Review Finds

When temperatures plunge far below freezing, the lithium-ion batteries that power everything from smartphones to electric cars begin to fail in ways that are both predictable and dangerous. The organic liquid electrolytes at the heart of these cells thicken as their viscosity rises, lithium ions move sluggishly between electrodes, charge-transfer kinetics slow to a crawl, and the risk of lithium plating and irreversible capacity loss climbs sharply. In the worst cases, the liquid electrolyte itself can freeze, leaving a battery that is not merely useless but potentially hazardous. A new comprehensive review argues that all-solid-state batteries, which replace the fragile liquid with a non-flammable, non-freezing solid electrolyte, could be the answer for energy storage in the harshest cold environments on Earth and beyond.

The review, published in Nano-Micro Letters, was conducted by researchers from the University of Wollongong, Sungkyunkwan University, and Hanyang University, led by Professor Junyoung Mun, Professor Taeseup Song, and Professor Jung Ho Kim. Rather than cataloguing isolated laboratory results, the team set out to map the entire landscape of low-temperature all-solid-state batteries, identifying the fundamental challenges, synthesising recent advances, and laying out strategies for the future. Their central message is that reliable sub-zero performance cannot be achieved by improving any single component in isolation; it demands a system-level strategy that integrates materials design, interface engineering, electrode architecture, and cell engineering simultaneously.

The appeal of solid electrolytes in extreme cold rests on a simple physical contrast. Because they are solids, they do not freeze, and their ionic conductivity remains relatively stable at sub-zero temperatures where liquid electrolytes collapse. This makes all-solid-state batteries attractive candidates for electric vehicles operating in winter climates, military communication systems that must function in any conditions, polar exploration equipment, and space missions, where a battery failure can compromise an entire mission. The review frames these applications not as distant aspirations but as realistic targets, provided the remaining scientific obstacles can be overcome.

Those obstacles fall into three interconnected categories. The first is suppressed lithium-ion transport. At low temperatures, lithium ions require sufficient thermal energy to overcome the migration barriers within the solid electrolyte and at electrode surfaces, and when that energy is scarce, ion mobility drops and the whole cell slows down. The second is increased interfacial resistance. Side reactions at the interfaces between electrodes and electrolyte can generate resistive interphases, products that insulate against lithium-ion movement and further impede charge transfer precisely when fast kinetics are needed most.

The third category is mechanical instability, a problem that is often overlooked in discussions of battery cold-weather performance but becomes critical in solid-state systems. As temperatures fall, materials contract, and in a battery built entirely from rigid solids this interfacial contraction can open gaps between particles and electrodes. Microcracking and contact loss disrupt the continuous pathways that lithium ions need to travel, increasing polarisation and degrading capacity. Because these three factors interact and reinforce one another, the authors argue that treating them independently will never deliver robust low-temperature performance; only an integrated approach can succeed.

Within materials design, the review identifies three major strategies. The first is improving charge transport itself. Solid electrolytes with high ionic conductivity and low activation energy barriers can facilitate lithium-ion migration even in deep cold, while optimised electrode materials accelerate the reaction kinetics at the interfaces. Recent examples span polymer, amorphous, sulfide, and oxide-based solid electrolytes, all engineered to maintain efficient ion transport at temperatures as low as minus 60 degrees Celsius. One striking case is an amorphous lithium nitride tantalum chloride based electrolyte, which maintained ionic conductivities of 0.5, 0.29, and 0.07 millisiemens per centimetre at minus 30, minus 40, and minus 60 degrees Celsius respectively, figures that demonstrate how far amorphous design can push low-temperature conductivity.

The second strategy is suppressing the interfacial side reactions that quietly strangle a cold battery. Chemically unstable electrode-electrolyte interfaces can form products that insulate against lithium ions, and the resulting resistance increase is especially damaging at low temperatures where the cell has little kinetic headroom to spare. The review highlights approaches including surface modification, the deliberate construction of protective interphases, and molecular-level control of electrolyte components, all aimed at suppressing these parasitic reactions while preserving the lithium-ion transport pathways that the cell depends on. The goal is a stable interface that neither reacts away nor blocks the ions it is meant to conduct.

The third strategy addresses the mechanical dimension: enhancing physical connectivity throughout the cell. Because thermal contraction and microcracking can sever the intimate solid-solid contact on which solid-state batteries rely, maintaining that contact is essential. The review describes how optimising particle size, electrode architecture, and interfacial structures can improve ionic percolation, the continuous network of pathways that ions follow through the electrode, and can regulate lithium deposition so that contact loss and dendrite formation are mitigated. Dendrites, the needle-like lithium structures that can pierce electrolytes and short-circuit cells, remain a concern even in solid systems, and controlling how lithium deposits at low temperatures is part of the same engineering challenge.

The progress documented in the review is substantial. Optimised solid electrolytes have enabled cells to deliver 137.6 milliampere-hours per gram with 83.5 percent capacity retention after 100 cycles at minus 30 degrees Celsius, a level of performance that would have seemed unattainable for solid-state systems only a few years ago. Sulfide-based systems have achieved 81.2 milliampere-hours per gram with 97 percent retention after 200 cycles at minus 20 degrees Celsius, showing that durability as well as capacity can be preserved in the cold. Other designs have pushed the operational envelope even further, demonstrating functioning cells at minus 40 and even minus 60 degrees Celsius, temperatures at which conventional liquid-electrolyte lithium-ion batteries are effectively dead.

Looking ahead, the authors caution that future breakthroughs will require more than simply raising ionic conductivity numbers. Understanding the temperature-dependent rate-limiting steps that govern how a cold cell actually fails, stabilising solid-solid interfaces against both chemical and mechanical degradation, preventing dendrite growth, and maintaining mechanical contact must all be addressed together. They point to a suite of advanced tools expected to guide this work: in situ and operando characterisation that watches batteries as they operate, cryogenic electrochemical analysis, first-principles calculations, three-dimensional modelling, and artificial-intelligence-assisted optimisation. Together, these methods promise deeper insight into lithium-ion dynamics and a more rational design of next-generation cells. If the integration of materials, interfaces, electrodes, and system-level engineering succeeds, the result would be safe, reliable batteries capable of powering electric vehicles, unmanned aerial vehicles, satellites, space suits, and deep-space probes through conditions where battery failure today carries serious consequences, opening a new chapter for energy storage in polar, military, aerospace, and other extreme environments.

Subject of Research: Low-temperature performance and design strategies of all-solid-state batteries

Article Title: Low‑temperature all‑solid‑state batteries

Article References: Low‑temperature all‑solid‑state batteries. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: all-solid-state batteries, solid electrolytes, low-temperature batteries, lithium-ion transport, interfacial resistance, ionic conductivity, dendrite formation, energy storage, extreme environments, space applications, electrode architecture, cryogenic electrochemistry