Boosting the performance of lithium metal capacitor with a Li composite anode

Abstract : Lithium metal capacitor (LMC), inheriting the merits of the lithium metal battery with an high energy density and an outstanding power capability comparable to supercapacitor (SCs), exhibits tremendous potential for next-generation energy storage systems. However, the application of Li metal anode is plagued by the formation of Li dendritic, which results in the uncontrollable volume expansion, potential safety hazards and even the premature failure. Here, a high-performance LMC based on a dendrite-free and resource-efficient three-dimensional Li composite anode with robust solid-electrolyte interphase (SEI) is reported. The constructed LMC with this advanced Li composite anode achieves a record-high energy density of 492 Wh kg-1 (~1.8 times higher than state-of-the-art value for lithium-ion hybrid capacitors, LICs) and a comparable power density of 28.5 kW kg1 to SCs as well as a long-term cyclability of over 2500 cycles. Furthermore, the overall perfromance of LMC is further evaluated by employing a Li dendrite-free flexible carbon nanotube network current collector, the constructed LMC based on the weight of the entire device still delivered a high energy density of 115.6 Wh kg-1. This work provides a very efficient stratergy for boosting the performance of LMC by constructing dendrite-free Li metal composite anodes.