Self-assembly of N,S-MXene/3DPC heterostructure with multiple charge transfer channels for high-performance supercapacitors and sodium-ion batteries

Abstract

Individual MXene (Ti3C3Tx) films tend to re-accumulate, seriously reducing the electrochemical properties. Herein, a viable hydrothermal method is being adopted to achieve the self-assembly of N and S co-doped three-dimensional porous carbon (3DPC) with conductive networks and MXene. For SCs, the N,S-MXene/3DPC electrode displays 412.7 F g−1 at 1 A g−1. When all-solid-state asymmetric SCs (ASCs) are manufactured with active carbon, the N,S-MXene/3DPC//AC ASCs present 210.5 F g−1 at 1 A g−1 and retain 97.5% of initial cycle through 5000 rotations. The energy density reaches its maximum of 94.7 Wh kg−1 at 900 W kg−1. In addition, the N,S-MXene/3DPC anode of SIBs demonstrates a reversible capability of 465.5 mAh g−1 at 0.2 A g−1. It also sustains a remarkable 72.9% preservation of capacity over 1000 rotations at 2.0 A g−1. The excellent electrochemical performance is attributed to following points: 3DPC with conductive networks can provide multiple transfer paths for ions and charges and support MXene. The co-doping of N and S for 3DPC can provide numerous active sites for electrochemical reactions, while the addition of MXene improves conductivity and mechanical stability. The N,S-MXene/3DPC material and its preparation method exhibit great potential for application in the field of electrochemical energy storage.