Harnessing Lithiophilic Hetero-Interfacial Chemistry for Stable Lithium Metal Batteries with Low Negative/Positive Capacity Ratios.

Lithium (Li) metal batteries hold great promise for next-generation energy storage due to their high energy density. However, their application is hindered by uncontrollable Li plating/stripping, leading to limited cycle life, especially under practical conditions with a low negative/positive (N/P) capacity ratio. Here, it is demonstrated that stable cycling of low N/P ratio Li metal batteries can be realized by harnessing hetero-interfacial redox chemistry to regulate Li nucleation and deposition behavior. It is shown that replacing pure Li metal with intercalated Li in graphite facilitates the formation of an increasingly lithiophilic heterointerface upon discharge, which homogenizes Li deposition during subsequent charge, resulting in highly reversible Li plating/stripping with minimal active Li loss under lean Li conditions. This enables Li metal cells with a Li/graphite hybrid anode to demonstrate remarkable improvements in cycling life, even with an N/P ratio as low as 0.4, compared to those with a pure Li metal anode. This strategy provides new insights into the role of hetero-interfacial chemistry in constructing highly reversible composite anodes for high-energy and long-cycling Li metal batteries.