Self-smoothing anode for achieving high-energy lithium metal batteries under realistic conditions

Despite considerable efforts to stabilize lithium metal anode structures and prevent dendrite formation, achieving long cycling life in high-energy batteries under realistic conditions remains extremely difficult due to a combination of complex failure modes that involve accelerated anode degradation and the depletion of electrolyte and lithium metal. Here we report a self-smoothing lithium–carbon anode structure based on mesoporous carbon nanofibres, which, coupled with a lithium nickel–manganese–cobalt oxide cathode with a high nickel content, can lead to a cell-level energy density of 350–380 Wh kg−1 (counting all the active and inactive components) and a stable cycling life up to 200 cycles. These performances are achieved under the realistic conditions required for practical high-energy rechargeable lithium metal batteries: cathode loading ≥4.0 mAh cm−2, negative to positive electrode capacity ratio ≤2 and electrolyte weight to cathode capacity ratio ≤3 g Ah−1. The high stability of our anode is due to the amine functionalization and the mesoporous carbon structures that favour smooth lithium deposition. Metallic lithium wets a functionalized mesoporous carbon film to create a self-smoothing anode that, in conjunction with a standard lithium nickel–manganese–cobalt cathode, delivers long cycling life, 350 Wh kg−1 high-energy cells under realistic conditions.