Preparation of MoP-based quasi-two-dimensional belt-like composite fibers and its performance modulation for sodium/potassium ion storage

Beyond round nanofibers, electrospinning method is able to fabricate thin fibers with various cross-sectional shapes. In this work, using phosphomolybdic acid to trigger the polymerization reaction of pyrrole with addition of tin salt for the filler of carbon fibers, we prepared quasi-two-dimensional thick belt-like fibers through single spinneret electrospinning. The side-by-side welding nanofiber bundles with dog-bone-shaped cross-section improved the connection between fibers, endowing the fiber films with some flexibility and enabling it to be used as freestanding electrode. Employed as anode for sodium/potassium ion storage, the carbon fiber encapsulated MoP/SnO2 material exhibited promising electrochemical performance. Controlling the collection process of electrospinning, the electrode mass loading can be increased to 10 mg cm-2. Combined with surface selenizing modification, the performance of as-prepared MoP/SnO2/MoSe2 was further improved, which exhibited areal capacity about 1.5 mAh cm-2 as anode for sodium/potassium ion storage with mass loading of 8-9 mg cm-2.