Large Interlayer Distance and Heteroatom-Doping of Graphite Provide New Insights into the Dual-Ion Storage Mechanism in Dual-Carbon Batteries

Dual-ion batteries (DIBs) is a promising technology for large-scale energy storage. However, it is still questionable how material structures affect the anion storage behavior. In this paper, we synthesis graphite with an ultra-large interlayer distance and heteroatomic doping to systematically investigate the combined effects on DIBs. The large interlayer distance of 0.51 nm provides more space for anion storage, while the doping of the heteroatoms reduces the energy barriers for anion intercalation and migration and enhances rapid ionic storage at interfaces simultaneously. Based on the synergistic effects, the DIBs composed of carbon cathode and lithium anode afford ultra-high capacity of 240 mAh g⁻¹ at current density of 100 mA g⁻¹. Dual-carbon batteries (DCBs) using the graphite as both of cathode and anode steadily cycle 2400 times at current density of 1 A g⁻¹. Hence, this work provides a reference to the strategy of material designs of DIBs and DCBs.