Challenges and Opportunities for Fast Charging of Solid-State Lithium Metal Batteries

In this Perspective, we assess the promise and challenges for solid-state batteries (SSBs) to operate under fast-charge conditions (e.g., <10 min charge). We present the limitations of state-of-the-art lithium-ion batteries (LIBs) and liquid-based lithium metal batteries in context, and highlight the distinct advantages offered by SSBs with respect to rate performance, thermal safety, and cell architecture. Despite the promising fast-charge attributes of SSBs, we must overcome fundamental challenges pertaining to electro-chemo-mechanics interaction, interface evolution, and transport-kinetics dichotomy to realize their implementation. We describe the mechanistic implications of critical features including plating-stripping crosstalk, metallic filament growth, cathode microstructure, and interphase formation on the fast-charge performance of SSBs. Toward achieving the eventual goal of fast-charge in SSBs, we highlight both intrinsic (e.g., interface design, transport properties) and extrinsic (e.g., temperature, pressure) design factors that can favorably modulate the mechanistic coupling and cross-correlations. Finally, a list of key research questions is identified that need to be answered to gain a deeper understanding of the fast-charge capabilities and requirements of SSBs.