ACS Nano, DOI: 10.1021/nn200770p
The advanced battery system is critically important for a wide range of applications, from portable electronics to electric vehicles. Lithium ion batteries (LIBs) are presently the best performing one, but they cannot meet requirements for more demanding applications due to limitations in capacity, charging rate and cyclability. One leading cause of those limitations is the lithiation-induced-strain (LIS) in electrodes that can result in high stress, fracture and capacity loss. Here we report that by utilizing the coating strategy, both the charging rate and LIS of SnO2 nanowire electrodes can be altered dramatically. The SnO2 nanowires coated with carbon, aluminum, or copper can be charged about 10 times faster than the non-coated ones. Intriguingly, the radial expansion of the coated nanowires was completely suppressed, resulting in enormously reduced tensile stress at the reaction front, as evidenced by the lack of formation of dislocations. These improvements are attributed to the effective electronic conduction and mechanical confinement of the coatings. Our work demonstrates that nanoengineering the coating enables the simultaneous control of electrical and mechanical behaviors of electrodes, pointing to a promising route for building better LIBs.