Folded-Graphene as an Ultrafast Cathode Material

For the cathode materials in SIBs, two major types of inorganic materials are dominating, namely layered transition-metal oxides and poly-anionic compounds. They can deliver a relatively high reversible capacity between 100 and 150 mA h g−1, along with a good cycling stability. However, compared with lithium, the larger ion size of sodium usually induces severe structural distortion to electrode and inferior charge storage kinetics due to the limited diffusion capability.