Phase change-induced heterointerface engineering of hollow sphere structured graphene oxide/layered double hydroxide composites for superior pseudocapacitive energy storage in lithium-ion batteries

Abstract

Integrating transition metal oxides with carbon-based materials through chemical heterointerface engineering presents a promising approach for achieving enhanced ionic/electrical conductivity, additional interfacial storage space, and structural stability, facilitating superior cyclic performance in energy storage systems. In this study, we synthesized a hierarchical heterostructure composite by combining graphene oxide with nickel–iron layered double hydroxides and promoted the formation of additional grain boundaries through phase change. Thus, we enhanced the pseudocapacitive contributions and the ion/charge transfer kinetics through nano-interfaces. These hybrid structures were formed through the layer-by-layer self-assembly of two-dimensional nanosheets. This design facilitates the construction of low-dimensional nanoarchitecture suitable for long-term cycling without ionic intermediates. Furthermore, to prevent agglomeration during the annealing process, we induced a phase change in NiCo-LDH under an inert atmosphere to fabricate reduced graphene oxide (rGO) embedded with amorphous nickel oxide (a-NiO) and NiFe₂O₄ nanoparticles, designated as rGO/a-NiO/NiFe₂O₄-HS. When utilized as an anode material for lithium-ion batteries, this material maintained an outstanding specific capacity of 1687.6 mA h/g at a current density of 100 mA g⁻¹ after 580 cycles. This nanostructuring and phase change strategy of the two-dimensional heterostructures can effectively promote the development of high-performance electrode materials based on the pseudocapacitive mechanism.