Realizing High Volumetric Lithium Storage by Compact and Mechanically Stable Anode Designs

With the continuing demand for the minimization of electrochemical energy storage devices, the volumetric performance has become equally important as the gravimetric metrics for rechargeable batteries used in limited spaces. High-capacity anode materials promise to significantly improve the volumetric performance of lithium-ion batteries, but the issues of nanosizing and mechanical instability induced by their large volume changes during cycling generally prevent their practical use. In this Perspective, we focus on the importance of mechanical stability designs and highlight internal densification as an ideal solution for the large-volume-change anode nanomaterials to achieve both good gravimetric and volumetric performance. We discuss the strategies based on the use of carbons in high-density material construction, precise void preservation, and stress management to address the mechanical instability issues in terms of materials, electrodes, and devices. Finally, future ways of solving these issues with compact lithium storage are suggested.