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.