Self-supported Li3VO4/N doped C fibers for superb high-rate and long-life Li-ion storage

Abstract

The high-rate Li-ion storage of Li₃VO₄-based electrodes has been hindered by unsatisfactory reaction kinetics caused by specific challenge in morphology and structure regulation. Self-supported Li₃VO₄/N doped C fibers (SS LVO/NC NFs) with foldability and the specific architecture of LVO nanoparticles embedded homogeneously in interlaced NC fibers are designed for the first time via a modified electrospinning approach. The morphological merits of the LVO/NC NFs and the structural merits of the integral electrode are well integrated in the SS LVO/NC NFs, resulting in continuously excellent reaction kinetics and superb high-rate performance. After 850 cycles of repeated rate performance testing from 0.5 to 5 A g⁻¹, the discharge capacity could restore to 592.3 mA h g⁻¹ when directly reverting the current back to 0.5 A g⁻¹. When gradually reducing the current from 5 to 0.5 A g⁻¹, the SS LVO/NC NFs could deliver a high discharge capacity of 553.2 mA h g⁻¹ after repeated rate performance testing from 5 to 0.5 A g⁻¹ over 820 cycles. When simulating the practical application under a high charge/discharge current of 4/6 A g⁻¹, the SS LVO/NC NFs could still deliver a high discharge capacity of 230.4 mA h g⁻¹ after 8000 cycles. The excellent performance and the foldability of the SS LVO/NC NFs endow it with potential application in wearable devices.