Long-cycle-life, high-capacity silicon anodes and methods of making and using the same

Abstract

Materials, methods, electrodes, and devices related to high-energy-density, long-life Li-ion batteries are provided. The lithium-ion anode material contains a porous core with silicon and optionally carbon nanotubes, and a dense shell made from lithium vanadium oxide having a disordered rocksalt structure. The lithium vanadium oxide functions as a solid-state mediator layer for the anode material and overcomes the well-known problem of significant volume increase when silicon is lithiated. The lithium vanadium oxide possesses mechanical robustness and prevents electrolyte penetration. For these reasons, the anode material forms a highly stable interface with the battery electrolyte. Experimental data is presented and discussed to demonstrate embodiments of the technology. It is shown that the silicon anode material can reversibly deliver a specific capacity higher than 2500 mA·h/g. The anode material exhibits excellent cycling stability and calendar life at room temperature as well as elevated temperature.