Harnessing Controlled Anionic Redox for High-Efficiency Prelithiation in Anode-Free Lithium Metal Batteries

Anode-free lithium metal batteries (AFLMBs), which forego the use of lithium metal anodes, represent a compelling path toward ultrahigh energy density alongside enhanced safety, cost reduction, and environmental sustainability. The development of high-performance AFLMBs has centered on three key strategies: leveraging the irreversible capacity as a lithium reservoir, innovating electrolyte, and modifying the anode current collector. However, the absence of an external lithium source continues to plague AFLMBs with inadequate cycling stability. This Perspective examines various approaches to address this fundamental limitation, highlighting prelithiation driven by irreversible anionic redox reactions at the cathode as a particularly promising solution. We critically evaluate recent advances in prelithiation techniques and outline future research directions. Specially, we propose that exerting precise control over the anionic redox process is pivotal to unlocking high-performance AFLMBs. By inspiring further research into regulated irreversible chemistry for lithium compensation, this Perspective aims to pave the way for durable, high-energy AFLMBs. Ultimately, we envision that the integration of controlled anionic redox with an advanced electrolyte and interphase engineering will establish a comprehensive design framework to accelerate the commercialization of AFLMBs.