Synthesis of heterointerfaces in NiO/SnO2 coated nitrogen-doped graphene for efficient lithium storage

Abstract

Currently, it remains a challenge to make comprehensive improvements to overcome the disadvantages of volume expansion, Li₂O irreversibility and low conductivity of SnO₂. Heterostructure construction has been investigated as an effective strategy to promote electron transfer and surface reaction kinetics, leading to high electrochemical performance. Herein, NiO/SnO₂ heterojunction modified nitrogen doped graphene (NiO/SnO₂@NG) anode materials were prepared using hydrothermal and carbonization techniques. Based on the excellent structural advantages, sufficiently small NiO/SnO₂ heterojunction nanoparticles increase the interfacial density to promote Li₂O decomposition, and the built-in electric field accelerates the charge transport rate to improve the conductivity. The three-dimensional porous graphene framework effectively mitigates volume expansion during cycling and stabilizes the reactive interface of electrode materials. The results show that the NiO/SnO₂@NG mixture has high reversible specific capacity (938.8 mA h g⁻¹ after 450 cycles at 0.1 A g⁻¹), superior multiplicity performance (374.5 mA h g⁻¹ at 3.0 A g⁻¹) and long cycle life (685.3 mA h g⁻¹ after 1000 cycles at 0.5 A g⁻¹). Thus, this design of introducing NiO to form heterostructures with SnO₂ is directly related to enhancing the electrochemical performance of lithium-ion batteries (LIBs).