Dual interface engineering of NiO/NiCo2O4/CoO heterojunction within graphene networks for high-performance lithium storage

Abstract

Rational construction of multidimensional composites with abundant heterointerfaces is still a persistent challenge, especially dual interface structure. Herein, a facile interface engineering strategy has been put forward to construct NiO/NiCo2O4/CoO heterostructures within graphene networks by controlling salt-templated solvothermal reactions and calcination treatments. The heterostructure produces dual interfaces of NiO/NiCo2O4 and CoO/NiCo2O4. The resultant composite combines the merits of the unique properties of each component and exerts their synergistic effects. The density function theory calculations reveal that the interface structures can endow the hybrid with higher states at Fermi level, fast electron transfer, and efficient Li+ adsorption ability. Furthermore, benefiting from the abundant active sites and porosity, this unique porous structure can accommodate the volume expansion and promote the diffusion of electrolyte ions, which greatly boosts the electrochemical performances of hybrids. Consequently, the NiO/NiCo2O4/CoO/Gra heterostructure electrodes achieve a remarkably reversible capacity of 1932.8 mAh g−1 at 0.1 A g−1, a superior rate capability (1210.5 mAh g−1 at 1 A g−1), and impressive cycling stability of 83.5% after 500 cycles at 0.5 A g−1. This work provides a new insight of developing multiple heterostructures anode materials for high-performance energy storage and conversion.