Nanowire-Threaded NiZn Layered Double Hydroxide Nanocage Heterostructures for High-Performance Supercapacitors

Abstract

Layered double hydroxides (LDHs), featuring tunable compositions and unique layered structures, have been widely investigated as electrode materials for supercapacitors. However, their electrochemical performance is often limited by intrinsically low electrical conductivity and insufficient exposure of electrochemically active sites. Herein, Co-carbonate hydroxide (Co-CH) nanowire-threaded NiZn layered double hydroxide (NiZn-LDH) nanocage heterostructures are rationally constructed, in which one-dimensional Co-CH nanowires physically pass through and interconnect multiple hollow NiZn-LDH nanocages. The Co-CH nanowires form a one-dimensional backbone favorable for electron transport, while the electronically coupled Co-CH/NiZn-LDH interfaces promote interfacial charge redistribution and electronic-structure modulation, with complementary analyses supporting their p–n heterojunction characteristics. The hollow nanocages provide internal voids and porous channels that facilitate electrolyte penetration and ion accessibility. As a supercapacitor electrode, Co-CH@NiZn-LDH delivers a specific capacitance of 1805 F g^–1 at 1 A g^–1, approximately 78% higher than that of pristine NiZn-LDH (1015 F g^–1), and exhibits a capacitance retention of 76% at 30 A g^–1, compared with 34% for NiZn-LDH. Furthermore, the assembled Co-CH@NiZn-LDH//AC asymmetric supercapacitor achieves an energy density of 68 Wh kg^–1 at a power density of 800 W kg^–1. This work provides a nanowire-threaded nanocage heterostructure design strategy that integrates one-dimensional backbones, ion-accessible hollow LDH nanocages, and electronically coupled heterointerfaces for high-performance supercapacitor electrodes.