Design Principle of Structured Lithium Metal Anodes for High-Energy Batteries

Abstract

Lithium metal batteries (LMBs) promise the next generation of energy storage technology due to their ultra-high theoretical specific capacity and energy density. The realization of LMBs heavily relies on stable, high-capacity, and fast charging/discharging Li metal anodes (LMAs). However, plating/stripping of Li metal at the widely-used "hostless" Li foil is subjected to severe dendrite growth and low reversibility, challenging the practical application of LMAs. Unlike the conventional Li foil, LMAs with delicately-designed bulk structures, denoted as structured LMAs, regulate Li deposition behavior through the incorporated framework, providing an effective way of containing the inherent defects of LMAs, such as infinite volume expansion, uncontrollable growth of Li dendrites, and excessive side reactions with electrolyte. Despite much progress, the design of structured LMAs lacks a systematic summary and deep insight into the structure-property relationship. This review underlines the challenges in the design and preparation of structured LMAs and then categorizes and summarizes the current progress of research on structured LMAs in detail, highlighting the interplay of framework components in regulating the deposition behavior of Li metal. We also discuss the existing hurdles and possible design criteria of structured LMAs, and provide an outlook on some promising directions for future research. The aim of this review is to provide guidance for the rational design of LMAs with unique structures for the next generation of high-energy-density batteries.