Heterostructure design of Mn–Ni(OH)2@1T-MoS2 for enhanced aqueous asymmetric electrochemical capacitors

Abstract

Achieving high energy density in aqueous asymmetric electrochemical capacitors hinges on the development of electrode materials that combine exceptional capacitance with superior conductivity. Despite its high theoretical capacitance, Ni(OH)₂ is limited by low intrinsic conductivity, significantly limiting its performance. In this study, a Mn–Ni(OH)₂@1T-MoS₂ heterostructure was synthesized through a facile growth method, achieving significant electrochemical performance boost. The lattice matching at the heterointerface induces a controlled lattice expansion in Mn–Ni(OH)₂, while the interfacial interactions promote electron transfer from Mn–Ni(OH)₂ to 1T-MoS₂. These synergistic effects enhance conductivity and active site utilization, addressing the core challenges of pristine Ni(OH)₂. As a result, the heterostructure exhibits a high specific capacity of 244.2 mA h g⁻¹ at 1 A g⁻¹ and a rate capability of 51.4% at 12 A g⁻¹. Moreover, the assembled asymmetric electrochemical capacitor delivers an energy density of 61.67 W h kg⁻¹ at 600 W kg⁻¹ and maintains 72.7% capacity retention after 10 000 cycles at 5 A g⁻¹. This work not only highlights the critical role of heterointerfaces in enhanced electrochemical performance but also provides a robust strategy for designing high-performance energy storage systems.