A New Strategy for Maximizing the Storage Capacity of Lithium in Carbon Materials

Abstract A novel strategy for maximizing the lithium storage capacity of carbon materials is reported. To redesign the interior structure, a large amount of Li, 4 wt%, is doped into the carbon during its synthesis. The Li‐doped carbon is subsequently annealed, during which the diffusion of Li induces a disordered structure, thereby generating many nanocavities. The diffused Li atoms aggregate into a superdense state within the carbon structure; when the Li agglomerates escape from the carbon during the delithiation process, new void spaces are created at their location. Thus, the interior of carbon is evacuated to form a new structure capable of storing a large amount of Li, realizing a high reversible capacity during charging. At a rate of 1 C, the average reversible capacity of the material is three times higher than that of commercial graphite, with a stable cycling performance over 300 cycles. This is a remarkably improved Li storage performance for pure carbon, without the need for the silicon, tin, or transition metal oxide, that are becoming popular as next‐generation materials. Therefore, this novel strategy can potentially aid in the design of high‐performance materials via better carbon material design and combinations with other types of materials.