General Synthesis of Uniform Three-Dimensional Metal Oxides/Reduced Graphene Oxide Aerogels by a Nucleation-Inducing Growth Strategy for High-Performance Lithium Storage

Three-dimensional (3D) transition metal oxides/reduced graphene oxide aerogels (TMOs/rGO-G) have received great attention for boosting the performance of alkali-ion batteries owing to abundant active sites and a short lithium-ion diffusion path. In this paper, we designed a general self-assembly strategy for preparing uniform 3D porous TMOs/rGO-G (TMOs = CoO, MnO, Fe2O3) hybrids even with a very high TMOs content (especially >80% for CoO/rGO-G and Fe2O3/rGO-G). This strategy contains successive self-assembly processes: self-assembly nucleation of TMOs on GO nanosheets in N,N-dimethylformamide (DMF)/H2O mixed solvent and 3D reduction-assembly of the obtained precursor for hybrid hydrogels along with nucleation-inducing growth of TMOs. Benefiting from the 3D porous network for fast ion/electron transport and a uniform hybrid between TMOs and rGO with a high TMO content, the 3D TMOs/rGO-G demonstrates an impressive lithium storage performance with both outstanding rate capability and excellent cycling stability. Specifically, the 3D CoO/rGO-G delivers a reversible capacity of 1142.8 mAh g–1 after 100 cycles at 0.5 A g–1 and high pseudocapacitive lithium storage behavior with 93.1% at 2 mV s–1, leading to outstanding rate capability with 624.7 mAh g–1 at 8 A g–1, as well as excellent stability with 493.3 mAh g–1 over 800 cycles at 4 A g–1. This general strategy demonstrates a general method in the design and synthesis of uniform 3D porous TMOs/rGO-G for energy storage