Ever-Increasing Pseudocapacitance in RGO-MnO-RGO Sandwich Nanostructures for Ultrahigh-Rate Lithium Storage

Lithium ion batteries have attained great success in commercialization owing to their high energy density. However, the relatively delaying discharge/charge severely hinders their high power applications due to intrinsically diffusion-controlled lithium storage of the electrode. This study demonstrates an ever-increasing surface redox capacitive lithium storage originating from an unique microstructure evolution during cycling in a novel RGO-MnO-RGO sandwich nanostructure. Such surface pseudocapacitance is dynamically in equilibrium with diffusion-controlled lithium storage, thereby achieving an unprecedented rate capability (331.9 mAh g(-1) at 40 A g(-1), 379 mAh g(-1) after 4000 cycles at 15 A g(-1)) with outstanding cycle stability. The dynamic combination of surface and diffusion lithium storage of electrodes might open up possibilities for designing high-power lithium ion batteries.