N-doped graphene wrapped SnP2O7 for sodium storage with high pseudocapacitance contribution

Developing advanced electrode materials for sodium storage is hindered by the sluggish Na+ diffusion kinetics and terrible structure damage. Pseudocapacitance is believed as a promising solution to supply fast, large and stable sodium storage via surface-controlled behavior. Herein, a hybrid material approach is implemented to pursue pseudocapacitance contributed sodium storage by constructing nitrogen doped graphene nanosheets packed SnP2O7 particles. The rationally selected components and specific structure also provide advantages for electrolyte penetration and Na+ diffusion, fast charge transfer, and structure stability. Hence, the developed composite delivers anode performances for sodium storage with high capacity of 423 mAh g(-1) at 0.1 A g(-1) , good rate performance of 206 mAh g(-1) at 2 A g(-1) , and stable cyclic property (retention rate of -95% after 1000 cycles at 1 A g(-1)). Pseudocapacitance contribution is vital for the composite electrode, especially at high rate, dedicating a percentage as high as 89% to the total capacity at a sweep rate of 1 mV s(-1). This work demonstrates the promising potential of compositing graphene and conversion reaction material as pseudocapacitive electrode for sodium ion batteries. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Developing advanced electrode materials for sodium storage faces challenges such as slow Na+ diffusion kinetics and structure damage. Pseudocapacitance is seen as a promising solution for fast and stable sodium storage. A hybrid material approach with nitrogen-doped graphene nanosheets packed SnP2O7 particles has shown high capacity and stable cyclic property for sodium storage.