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 nanointerfaces. 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/NiFe2O4HS. When utilized as an anode material for lithium-ion batteries, this material maintained an outstanding specific capacity of 1687.6 mA h g- 1 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 highperformance electrode materials based on the pseudocapacitive mechanism.