Hierarchical micro-nano structure based NiCoAl-LDH nanosheets reinforced by NiCo2S4 on carbon cloth for asymmetric supercapacitor

Abstract

All-solid-state asymmetric supercapacitor based on hierarchical hybrid structure decorated with conductive NiCo 2 S 4 on NiCoAl-LDH has good energy density and power density. • NCA-LDH@NCS@CC is synthesized by a simple and low-cost hydrothermal method. • Hierarchical hybrid structure NCA-LDH@NCS is formed on carbon cloth. • NiCo 2 S 4 boosts overall electrical conductivity and hinders agglomeration of LDH. • NCA-LDH@NCS@CC//AC@CC is assembled with high energy density and cycle stability. Rational construction of microstructure and successful incorporation of multiple components offer a scalable strategy for applying electrode materials in asymmetric supercapacitors. Herein, a hierarchical hybrid structure of NiCoAl-layered double hydroxide (NCA-LDH) and ternary spinel NiCo 2 S 4 (NCS) on carbon cloth (CC) without binders is obtained through three-step hydrothermal reaction. The NCA-LDH@NCS@CC electrode exhibits outstanding electrochemical performance with 1775F g −1 at 1 A g −1 . Its capacitance retention is 79.6% when cycles reach 10 000 under 10 A g −1 , benefiting from the hierarchical hybrid structure and improved overall conductivity. A flexible solid-state asymmetric supercapacitor (FSASC) is assembled using NCA-LDH@NCS@CC and activated carbon coated on carbon cloth (AC@CC) for positive and negative electrodes, respectively. It possesses 33.13 Wh kg −1 under 750 W kg −1 , and also maintains a better cycling performance of 71.4% at 1 A g −1 after 10 000 cycles. Hierarchical hybrid NCA-LDH@NCS@CC electrode provides a favorable and scalable candidate for the development of FSASC device with superior performance.