Due to the large ionic radius and associated slow reaction kinetics of potassium ions, it is a major challenge to find suitable anode materials for potassium-ion batteries. Herein, we design porous antimony-based nanofibres via a simple, low-cost and large scalable method to promote the electrochemical performance of potassium-ion batteries. Unlike those traditionally treated in inert atmospheres, using the different decomposition processes of polyacrylonitrile and polyvinylpyrrolidone in air, we obtain antimony trioxide embedded in porous carbon nanofibres (Sb 2 O 3 @PCN). The porous structure can promote the permeation of electrolyte into electrode materials and increase the active sites of the redox reaction. The porous carbonaceous fibre skeleton structure establishes a fast ion transport channel and enhances the kinetic performance. In a concentrated 5 M potassium bis(fluorosulfonyl)-imide/dimethyl carbonate electrolyte, Sb 2 O 3 @PCN exhibits a stable discharge specific capacity of 437.3 mAh g -1 at a current density of 100 mA g −1 after 50 cycles, which is much higher than that treated in a N 2 atmosphere (247.5 mAh g -1 ). This method provides a new approach for the preparation of efficient potassium-ion battery electrode materials.
Xue Tian,Peng Zhang,Yizhi Liao,Razium A. Soomro,Bin Xu
Antimony-based anode materials are recognized for their high potassium storage capacities and appropriate operating potentials. However, the large volume expansion of Sb during the potassiation/depotassiation process, which results in a quick capacity decay, severely limits its practical application in potassium-ion batteries (PIBs). Here, a carbon-coated Sb/MXene heterostructure composite (CSM) is synthesized by adsorption of Sb 3+ on MXene nanosheets via Sb-O-Ti bonds followed by carbothermic reduction to construct dual-confined MXene@carbon conductive framework capable of withstanding high volume expansion of Sb and conducive to enabling accelerated electron transfer kinetics. The CSM composite, particularly CSM-700, when configured as an anode for PIBs, realized high capacity (484.4 mAh g −1 at 0.1 A g −1 ), an ultra-stable cycling performance with a high reversible capacity of 435.9 mAh g −1 at 0.1 A g −1 after 100 cycles corresponding to a capacity retention rate of 90.0%, and superior rate performance of 323.0 mAh g −1 at 1 A g −1 . The proposed strategy offers a simple route to construct high-performance Sb-based anodes for advanced PIBs.
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