General Synthesis of Graphene/Metal Oxide Heterostructures for Enhanced Lithium Storage Performance

Abstract

Graphene/metal oxide (rGO/MOx) heterostructures hold great promise for energy storage, yet a full understanding of their synthesis remains elusive. Herein, a general, efficient, and scalable synthesis strategy is designed for the preparation of various rGO/MOx heterostructure materials featuring robust interfacial interactions. The heterogeneous nucleation growth mechanism of metal oxides on graphene is elucidated through ex situ characterization and theoretical simulation. The surface of graphene oxide (GO) is enriched with reactive oxygen-containing functional groups, serving as potent nucleation sites that facilitate the rapid and heterogeneous nucleation of MOx grains. Simultaneously, a stable interface (C−O−M bond) is in situ formed between graphene and adsorbed metal ions during heat treatment, producing rGO/MOx heterostructure materials. Notably, the resultant rGO/CoO heterostructure material is employed as an anode and LiCoO2 as a cathode to assemble a soft packaging quasi-solid-state battery, which has demonstrated an impressive energy density of 341.4 Wh kg−1 and maintains outstanding capacity retention at 93.4% after 300 cycles at a 1C current. These findings provide valuable insights into the preparation and potential applications of rGO/MOx heterostructure materials for energy storage.