Graphite-Encapsulated Li-Metal Hybrid Anodes for High-Capacity Li Batteries

The drive to achieve high-energy-density lithium (Li)-ion batteries has attracted a tremendous amount of effort in the design of new materials. Although new electrode materials may take years, if not decades, to mature before they can become compatible with other components of Li-ion battery technology, exploring new phenomena on the existing electrode materials could offer many practical avenues for improving the existing technology. In this study, we report a convenient method of overcoming the capacity limit of conventional graphite anodes by reversibly plating and stripping Li metal within the internal space of massive artificial graphite particles. With a controlled specific capacity (744 mAh g−1) twice that of the state-of-art for graphite, we obtained stable charge-discharge cycling with a high Coulombic efficiency of ∼98.4% over more than 50 cycles at 0.2 C (74.4 mA g−1) in a carbonate electrolyte.