Towards high potential and ultra long-life cathodes for sodium ion batteries: freestanding 3D hybrid foams of Na7V4(P2O7)4(PO4) and Na7V3(P2O7)4@biomass-derived porous carbon

摘要: High potential sodium hosts have attracted enormous attention recently in view of the requirement for improving energy density ion batteries. Na7V4(P2O7)4(PO4) and Na7V3(P2O7)4 with operating potentials near 4.0 V versus Na+/Na are promising cathode candidates. But low conductivity, limited intercalation kinetics inferior stability remain critical drawbacks their practical applications. In this paper, design freestanding three-dimensional (3D) hybrid foams high hosts@biomass-derived porous carbon is reported. The biological fungus realizes formation highly graphene-like carbon, which constructs 3D framework polyanions. polyanion nanocrystals closely enwrapped by biomass derived build architecture. Both conductive skeleton hierarchically architecture favourable efficient electron transport. Furthermore, depressed structural deterioration rate improved contact between active material substrate achieved comparison conventional electrodes on basis dynamic studies. Without additional additive or binders, achieve desirable characteristics potentials, fast excellent cycling stability. Na7V4(P2O7)4(PO4)- Na7V3(P2O7)4-based retain 94% 91%, respectively, capacities after 800 cycles at alternative 20C 3C, demonstrating superior ultra long-term capability. Therefore, research provides a low-cost, widely applicable to construct long-life cathodes