Multi-level structural modulation enables fast lithium-ion transport in inorganic solid-state batteries

Solid-state lithium metal batteries (SSLMBs) are considered ideal candidates for the next-generation core technologies for development of clean energy storage and conversion systems owing to their inherent high energy density and exceptional safety. Nevertheless, the practical energy density, power characteristics, and cycling stability of SSLMBs are usually limited by sluggish charge transfer kinetics within and across solid-state components, including electrode, electrolyte, binder, and conductive additive materials. Therefore, understanding the intrinsic link between structure-charge transport-performance and improving charge transport kinetics in a heterogeneous solid system through structural modulation has become the key to comprehensively improving the electrochemical performance of SSLMBs. Herein, a unique perspective is proposed to optimize the short-range and long-range charge transport processes in SSLMBs through multi-level structural modulation at the electrode, solid electrolyte, and cell levels. We firstly summarize and evaluate the research progress in multi-level structural modulation. Then, the vital factors impacting structural regulation and regulation principles at the corresponding level are analyzed in depth. Furthermore, the extent of enhancement and limitations of various structural modulation approaches employed for charge transport are evaluated and compared. At the end, perspectives and suggestions were provided on principles for multi-level structural modulation toward fast charge transport kinetics in inorganic SSLMBs. This review will offer broadly applicable principles for the development of next-generation high-performance inorganic SSLMBs.