Incombustible Polymer Electrolyte Boosting Safety of Solid-State Lithium Batteries: A Review

Lithium-ion batteries with their portability, high energy density, and reusability are frequently used in today's world. Under extreme conditions, lithium-ion batteries leak, burn, and even explode. Therefore, improving the safety of lithium-ion batteries has become a focus of attention. Researchers believe using a solid electrolyte instead of a liquid one can solve the lithium battery safety issue. Due to the low price, good processability and high safety of the solid polymer electrolytes, increasing attention have been paid to them. However, polymer electrolytes can also decompose and burn under extreme conditions. Moreover, lithium dendrites are formed continuously due to the uneven charge distribution on the surface of the lithium metal anode. A short circuit caused by a lithium dendrite can cause the battery to thermal runaway. As a result, the safety of polymer solid-state batteries remains a challenge. In this review, the thermal runaway mechanism of the batteries is summarized, and the batteries abuse test standard is introduced. In addition, the recent works on the high-safety polymer electrolytes and the solution strategies of lithium anode problems in polymer batteries are reviewed. Finally, the development direction of safe polymer solid lithium batteries is prospected.

Automated summary

Lithium-ion batteries, known for their portability, high energy density, and reusability, are widely used but they can leak, burn, or explode under extreme conditions. Researchers propose using solid electrolytes to improve the safety of lithium-ion batteries, but even polymer electrolytes can decompose and burn. Furthermore, the uneven charge distribution on the lithium metal anode leads to the formation of lithium dendrites, causing potential short circuits and thermal runaway. This review summarizes the thermal runaway mechanism, discusses battery abuse test standards, reviews recent works on high-safety polymer electrolytes, and considers solution strategies for lithium anode problems in polymer batteries, aiming to prospect the development of safe polymer solid lithium batteries.