NiCo layered double hydroxide anchored on Mxene/tannin carbon cryogel composite with 3D hierarchical sea urchin-like structure for asymmetric supercapacitors

Authors： Yuling Lan, Shirui Wang, Zhanhui Yuan* and Weigang Zhao*

Abstract： Layered bimetallic hydroxides have attracted considerable attention as electrode materials for supercapacitors, with various modification strategies being explored to enhance their practical electrochemical performance. In this study, we present a simple and robust bottom-up synthesis method for fabricating a 3D hierarchical interwoven NiCo-LDH@MT-based electrode through a microwave-assisted hydrothermal co-assembly process, using MXene, NiCo-LDH, and tannin-based cryogel. The resulting NiCo-LDH@MT electrode exhibited an exceptional specific capacitance of 1210.55F g−1 at a current density of 1 A g−1, along with an impressive rate capability of 80.05 %, compared to 53.3 % for the pure NiCo-LDH electrode. Asymmetric supercapacitor devices assembled using NiCo-LDH@MT as the positive electrode and MXene-TPUF as the negative electrode demonstrated a high energy density of 48.22 Wh kg−1 at a power density of 946.5 W kg−1. Furthermore, the devices achieved a remarkable capacity retention of 93.2 % and a Coulombic efficiency of 100 % after 10,000 cycles at 10 A g−1. The outstanding specific capacitance, long-term stability, and excellent energy and power density of the NiCo-LDH@MT-based asymmetric supercapacitor underscore its significant potential for energy storage applications.

DOI:https://doi.org/10.1016/j.cej.2024.157471