Single-ion conducting soft electrolytes for all-solid-state lithium metal batteries operating under ambient conditions

Abstract

Despite their potential as a post lithium (Li)-ion battery, all-solid-state Li metal batteries (ASSLMBs) have struggled with electrochemical sustainability and ambient operation limitations. This challenge stems from lack of reliable solid-state electrolytes. Here, we demonstrate a new class of single-ion conducting soft electrolyte (SSE) for practical ASSLMBs. Coupling nonflammable coordinated electrolytes with ion-rectifying compliant skeletons enables the SSE to provide high ionic conductivity, Li-ion transference number close to unity, electrochemical stability, flexibility, and nonflammability, while mitigating grain-boundary/interfacial resistances. Rheology-tuned SSE pastes, in combination with UV curing-assisted multistage printing, allow fabrication of seamlessly integrated ASSLMBs (Li metal anode/SSE/LiNi0.8Co0.1Mn0.1 cathode) under ambient conditions. Benefiting from the unique chemistry of SSE and monolithic cell architecture, the ASSLMB full cell exhibits stable charge/discharge performance (cyclability, rate capability, and bipolar configurations with tunable voltages) under ambient operating conditions, along with low-temperature performance, foldability, and safety which are difficult to achieve with conventional inorganic electrolyte-based ASSLMBs.