Electrospinning Fabrication and Enhanced Performance of 3D Li₃V₂(PO₄)₃/C Fiber Membrane as Self-standing Cathodes for Li-ion Battery

A three-dimentional(3D) long-range networking Li₃V₂(PO₄)₃/C fiber membrane was fabricated by a modified electrospinning method and a hot-press calcination process. The combined use of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) promotes the growth of Li₃V₂(PO₄)₃ crystals on the surface of the conductive carbon fibers. The adopted hot-press process is favorable to achieve a flexible 3D long-range networks. The Li₃V₂(PO₄)₃/C fiber membrane calcined at 800 °C for 20 h with a high specific surface area of 186.4 m²/g and a wide pore size distribution can be used as self-standing, binder-free cathodes and exhibits excellent electrochemical performances. The discharge capacity is up to 196.8, 150.4 and 145.2 mAh/g at the current density of 0.1 C, 5 C and 10 C, respectively. After the rate tests, the Li₃V₂(PO₄)₃/C fiber membrane cathode still exhibits an excellent cycle stability at 5 C with a discharge capacity of 143.4 mAh/g after 850 cycles. These high performances are ascribed to the enhanced electronic and ionic conductivities owing to the 3D long-range conductive networks, well-crystallized Li₃V₂(PO₄)₃ particles in-situ grown on the surface of carbon fibers and the novel binder-free, self-standing structural characterics.