NiCoMn-Layered Double Hydroxide Porous Hollow Nanocagesfor High-Performance Asymmetric Supercapacitors

Abstract

As a core component of energy storage devices, the performance breakthrough of supercapacitors is crucial for the development of renewable energy systems, yet the synergistic improvement of energy density and cycle life remains a long-standing technical challenge in this field. Although layered double hydroxides (LDHs) with adjustable interlayer structures have emerged as promising high-capacity electrode candidates, existing mono/bimetallic LDHs are generally limited by poor conductivity and structural collapse during cycling, resulting in practical capacities often below theoretical values. This study proposes an innovative bimetal-templated strategy to synthesize ternary NiCoMn-LDHC with unique porous hollow nanocage structures through the construction of CoMn-based zeolitic imidazolate framework (CoMn-ZIF) precursors followed by controlled annealing and carbonization. The synergistic effects of ternary metals combined with hierarchical porous architecture endow the material with exceptional electrochemical properties. The NiCoMn-LDHC electrode demonstrates a high specific capacity of 261.33 mAh g^–1 at 1 A g^–1 and maintains 92.85% capacity retention after 10,000 cycles at 5 A g^–1. Furthermore, the asymmetric supercapacitor NiCoMn-LDHC//AC assembled with activated carbon (AC) exhibits outstanding electrochemical characteristics, achieving an energy density of 30.22 Wh kg^–1 at a power density of 800 W kg^–1. Remarkably, it retains 91.09% capacity retention even after 10,000 cycles at 5 A g^–1.