Boosting the electrochemical performance of 3D composite lithium metal anodes through synergistic structure and interface engineering

Construction of three-dimensional (3D) composite lithium metal anodes (LMAs) based on Li melt-infusion into a 3D porous scaffold has been demonstrated to be effective for solving the issue of the considerable relative volume change of LMAs during Li plating/stripping. However, little attention has been paid to controllable regulation of the structure and interface of 3D composite LMAs. In this study, 3D composite LMAs, namely Li–AuLi3@CF electrodes, are firstly fabricated by infusion of molten Li into carbon fiber (CF) paper modified with nanoporous gold (NPG) which is converted to AuLi3 after infusion. We herein demonstrate a synergistic structure and interface engineering strategy realized by a simple and effective pre-stripping protocol to initially expose a portion of the 3D AuLi3@CF scaffold to create “PS-Li-AuLi3@CF” electrodes, which greatly boosted the electrochemical performance. Symmetrical Li|Li cells with PS-Li-AuLi3@CF electrodes show an overpotential of 111 ​mV after cycling at a current density of 0.5 ​mA ​cm−2 for 1800 ​h. Additionally, Li|LiFePO4 (LFP) and Li|sulfurized polyacrylonitrile (SPAN) full cells with PS-Li-AuLi3@CF electrodes exhibit a high capacity retention of 96.1% with a Coulombic efficiency (CE) of 99.2% after 1000 cycles at 5C, and a capacity retention of 70.6% with a CE of 99.8% after 1000 cycles at 2C, respectively. This work provides a simple and highly effective method for engineering the structure and interface of 3D composite LMAs to boost their electrochemical performance for high-energy-density rechargeable lithium metal batteries (LMBs).