Cu1.81S-doped carbon modified copper foam as current collector for high-performance lithium metal batteries

Abstract

Lithium metal battery has shown extraordinary promise for electrochemical energy storage due to high theoretical capacity and low reduction potential. However, its energy density improvement and commercial application are seriously limited by the inevitable formation of dendrites and dead lithium and the infinite change of electrode volume during repeated charge-discharge processes. In this work, a three-dimensional Cu foam decorated with a lithophilic sulfide doped carbon layer (Cu1.81S-C@CF) is used as an advanced 3D host for long-life lithium metal anode. The average current density is effectively reduced and the volume change is accommodated by the three-dimensional porous structure. Moreover, the effects of different reaction temperature and time on surface morphology and structure of lithophilic layer on 3D current collector is also systemically studied. The Cu1.81S-doped carbon layer prepared at a deposition temperature of 800 °C for 2 h (Cu1.81S-C@CF-800–2) exhibits excellent lithium dendrite inhibition ability. The symmetrical battery with Cu1.81S-C@CF-800–2 as a lithium host could operate for over 6000 h with a low overpotential (about 14.9 mV) without intense voltage fluctuation. Moreover, the Li@Cu1.81S-C@CF-800–2 full battery matched with LiCoO2 (LCO) cathode exhibits a high initial capacity of 142.78 mAh g−1 and excellent capacity retention of 96.4% at 0.2 C, with an average CE of 99.6% over 120 cycles. This work not only successfully prepares a long-life lithium metal anode, but also provides a new strategy for preparing and optimizing lithophilic layer of 3D current collectors.