Loss and Recovery of Effective Lithium in Anode‐Free Solid‐State Lithium Metal Batteries

Anode-free solid-state lithium (Li) metal batteries (AFSSLMBs), with anticipated high energy density and cost-effectiveness, high safety, and simplicity of fabrication, are considered to have great potential in becoming promising alternatives for next-generation electrochemical energy storage devices. Unfortunately, the inefficiency of Li plating/stripping and the rapid capacity decay during cycling have severely hindered the further development of AFSSLMBs. Accordingly, to cope with these faced challenges, enormous efforts have been made in the most recent years. However, a comprehensive review entirely focusing on AFSSLMBs seems not available in terms of the loss and recovery of effective Li. Herein, based on the current understanding of AFSSLMBs, the essential causes of the main challenges faced by AFSSLMBs are attributed to irreversible Li loss and sluggish Li kinetics. Subsequently, five main types of advanced strategies for promoting AFSSLMBs' performance from various critical components are categorized and summarized along with the main line of avoiding effective Li loss, in which the contents from impactful articles published in the most recent one to two years are predominantly comprised. Finally, the challenges and possible future directions of AFSSLMBs are proposed, aiming to accelerate the rapid research and development for practical applications and commercialization of this advanced technology.