(A) study of elastomeric electrolytes for high-energy solid-state lithium-metal batteries

Abstract

Demand for lithium (Li)-ion batteries is increasing explosively due to the commercialization of electric vehicles, and next-generation batteries improving mileage and safety are receiving attention. The all-solid-state lithium-metal batteries (ASSLMBs) replace the highly flammable liquid electrolyte between Li-metal anode and cathode with the solid electrolyte. ASSLMBs can charge a large capacity and improve safety compared to the Li-ion batteries currently in use. Solid electrolytes for ASSLMBs are mainly divided into polymer-based, oxide-based, and sulfide-based electrolytes. The solid polymer electrolytes (SPEs) have advantages for large-scale manufacturing due to low cost, nontoxicity, low-temperature process and lightweight, whereas have problems of low ionic conductivity at room temperature and poor stability during battery charging and discharging. Although many studies have been done on PEO-based SPEs to solve the problems of SPEs, their low ionic conductivity and low mechanical durability are still hindering commercialization. In this study, a new concept of elastomer-based polymer electrolytes are developed, and the relationships between the physical/chemical control of elastomer-based polymer electrolytes and performance of ASSLMBs are investigated to increase potential for commercialization of ASSLMBs. The elastomer-based polymer electrolytes simultaneously achieve high ionic conductivity comparable to liquid electrolytes and mechanical robustness through developing 3D interconnected structure of plastic crystal within elastomer matrix. With elastomer-based polymer electrolytes having these properties, ASSLMB realize the world’s highest energy density of 410Wh/kg. Then, the structures are variously controlled by adjusting the volume fractions of the elastomer/plastic crystal of the elastomer-based polymer electrolytes, and the importance of bicontinuous structure is demonstrated by investigating structure-property-performance relationships. The elastomer-based polymer electrolytes is expected to be a game changer for the commercialization of ASSLMBs.