Amorphous TiO2 inverse opal anode for high-rate sodium ion batteries

摘要

Potential applications of sodium-ion batteries (SIBs) have motivated significant research interest in grid-scale energy storage. However, large radius of Na ions results in different electrochemical behaves. Therefore, synergistic understanding of the differences is greatly interested for future development of SIBs. Surface availability for ions with poor affinity to electrode materials is critical to rate performance in SIBs, but yet has rarely been reported. Here, to overcome the obstacles of material platform, amorphous TiO2 inverse opal is employed as a proof-of-concept prototype to illuminate the effects of surface ion availability and its relationship between solvent wettability and rate capability. Within expectation, superior rate capabilities are achieved in return for enhanced solvent wettability, regardless of the type of electrolyte and the ion concentration in electrolyte. Even when the anode is cycled at a current density as high as 5000 mA g(-1), the reversible capacity could still retain a high value of similar to 113 mA h g(-1). Our concept opens up a promising avenue to realize full potential of designing electrode materials for SIBs by adjusting the surface kinetics. This understanding shall extend the design principle to electrode materials for highly effective energy storage using other transport ions and other storage mechanisms.