Deactivating Defects in Graphenes with Al2O3 Nanoclusters to Produce Long‐Life and High‐Rate Sodium‐Ion Batteries
The defects in graphene are deactivated by the coverage of Al2O3 nanoclusters, which suppress the irreversible decomposition of the sodium conductive salt in sodium‐ion battery electrolytes. An ion‐conducting, thin and homogenous solid electrolyte interphase is formed, resulting in high initial Coulombic efficiency, good rate capability, and cyclic stability for sodium‐ion storage. Abstract Carbon materials are the most promising anodes for sodium‐ion batteries (SIBs), but low initial Coulombic efficiency (ICE) and poor cyclic stability hinder their practical use. It is shown herein, that an effective but simple remedy for these problems can be achieved by deactivating defects in the carbon with Al2O3 nanocluster coverage. A 3D porous graphene monolith (PGM) is used as the model material and Al2O3 nanoclusters around 1 nm are grown on the defects of graphene. It is shown that these Al2O3 nanoclusters suppress the decomposition of conductive sodium salt in the electrolyte, resulting in the formation of a thin and homogenous solid electrolyte interphase (SEI). In addition, Al2O3 nanoclusters appear to reduce the detrimental etching of the SEI by hydrogen fluoride (HF) and improve its stability. Therefore, after the introduction of Al2O3 nanoclusters, the ICE, cyclic stability, and rate capability of the PGM are greatly improved. A higher ICE (70.2%) and capacity retention (82.9% after 500 cycles at 0.5 A g−1) than those of normally reported for large surface area carbons are achieved. This work indicates a new way to deactivate defects and modify the SEI of carbon materials, and hopefully accelerate the commercialization of carbon
Published in: "Advanced Energy Materials".