High mass-loading N-rGO-T-Nb2O5/CuNW composite membrane for high-rate lithium-ion capacitor anodes

High-performance lithium-ion capacitors (LICs) show tremendous application prospects in new energy vehicles and portable electronic devices due to their excellent electrochemical properties. However, the low active mass loading and poor reaction rate of the current anode seriously limit the rate performance of LIC. Herein, we developed a high mass-loading N-doped reduced oxide graphene (N-rGO)-T-Nb2O5/Copper nanowire (CuNW) (GNC) composite membrane as an anode for high-rate LICs, which was obtained by compressing the corresponding 3D composite aerogel. Importantly, Li+ can be rapidly embedded/detached in large lattice spacing of T-Nb2O5 and high adsorption capacity of N-rGO, improving the rate performance of the GNC anode. Furthermore, the use of trace CuNWs conductive network instead of conventional Cu foil can effectively reduce the self-weight of the composite membrane for enhancing the specific capacity of the electrode. In lithium-ion half-cell, the high mass-loading GNC-2 (6.19 mg·cm−2 in coin cell) possessed high specific capacity, large rate performance, and excellent cycling life. The LIC consisted of prelithiated GNC-2 and N-rGO exhibited high energy density (173.9 Wh·kg−1), and power density (5242.8 W·kg−1) with outstanding cycle stability (capacitance retention rate of 93.2 % after 10,000 cycles at 3 A·g−1).