Enhancing the Cycle Life of Lithium‐Anode‐Free Batteries through Polydopamine‐Coated Substrates

Abstract

Anode‐free lithium metal batteries (AFLMBs) show promise as a means of further enhancing the energy density of current lithium‐ion batteries, as they do not require conventional graphite anodes. The anode‐free configuration, however, suffers from inferior chemical stability of the solid electrolyte interphase (SEI) layer and experiences inhomogeneous lithium deposition during charge/discharge processes, resulting in rapid capacity fading. To address these issues, a carbonized polydopamine (CPD) coating is applied to the copper current collector. The CPD‐coated copper current collector promotes highly efficient and reversible lithium plating and stripping processes, resulting in a densely packed lithium deposition that significantly improves cycling stability. The anode‐free full cell, consisting of CPD‐coated copper current collector and a LiFePO4 cathode, demonstrates significantly improved electrochemical performance, with a capacity retention of more than 63% after 100 cycles at a current rate of 0.3C. The stability of the SEI layer and the presence of lithiophilic sites are verified through a range of techniques, including optical microscopy, Raman spectroscopy, X‐ray photoelectron spectroscopy, chronoamperometry, and electrochemical impedance spectroscopy. Based on these collective findings, it can be inferred that the use of CPD coating provides a simple way to enhance the electrochemical performance of AFLMBs.