Convenient room‐temperature synthesis of sulfur and nitrogen co‐doped NiCo‐LDH coupled with CNTs on NiCo foam as battery‐type electrode for high performance hybrid supercapacitor

Abstract

Abstract The convenient synthesis of the composite electrode with high supercapacitance performance plays an important role in practical application but is challenging. Herein, the carbon nanotubes (CNTs) coupled with low‐crystalline sulfur and nitrogen co‐doped NiCo‐LDH (denoted as SN‐NiCo‐LDH) nanosheets array are grown on NiCo foam (NCF) substrate by two convenient steps of metal induced self‐assembly and corrosion engineering, which present the advantages of operating at room‐temperature and low preparation costs. Benefiting from the S–N co‐doping and low‐crystallinity of NiCo‐LDH, the prepared SN‐NiCo‐LDH@CNTs@NCF electrode presents a topping charge capacity of 2470 C·g −1 (4.94 C·cm −2 ) at 5 mA·cm −2 . Furthermore, the fabricated asymmetry supercapacitor (ASC) achieves an extraordinary energy density of 77 Wh·kg −1 (0.617 mWh·cm −2 ) at a power density of 438 W·kg −1 (3.5 mW·cm −2 ) and outstanding stability (91% capacity retention after 5000 cycles at 20 mA·cm −2 ). Impressively, the structure evolution of NiCo‐LDH during the charge/discharge processes has been thoroughly elucidated by in‐situ Raman spectra. Therefore, this work verifies a powerful strategy and practical value for preparing composite electrodes with high supercapacitance performance, and also provides guidance for the rational design of the smart electrodes.