Realizing high-performance lithium ion hybrid capacitor with a 3D MXene-carbon nanotube composite anode

Abstract 3D MXene-carbon nanotube (3D MXene-CNT) architecture electrode was rationally prepared by a facile gel assembly and chemical vapor deposition (CVD) process to address the neglected issue of the serious re-stacking and lower specific capacity of MXene as lithium-ion batteries (LIBs) anode. Benefiting from the unique architectural structure, the as-prepared 3D MXene-CNT electrode demonstrates a high reversible capacity of 590 mA h g−1 at 0.1 A g−1 and excellent rate performance with a capacity of 191 mA h g−1 at 5.0 A g−1. On the basis of this advanced 3D MXene-CNT anode, a lithium-ion hybrid capacitor (LIHC) with outstanding electrochemical performance was demonstrated by matching a capacitor-type 3D nitrogen-doped framework activated carbon (3DNFAC) cathode. The device displays a high energy density of 201 Wh kg−1 at a power density of 210 W kg−1, and an impressive energy density of 92 Wh kg−1 even at a high power density of 21 000 W kg−1, as well as good capacity retention of 84.7% after 3500 cycles at 2.0 A g−1. This work opens a new way for designing advanced MXene-based composite anodes with excellent Li+ storage electrochemistry for lithium based batteries and hybrid capacitors.