Electrical energy storage (EES) technology plays a major part in todays’ society owing to the advances in hybrid and electric cars, portable electronic devices and grid storage backup for renewable energy utilization. Lithium ion batteries (LIBs) have dominated the EES market for the past several decades owning to their high-energy density and low cost. Despite the success, low specific capacity and low power rates still need to be addressed to meet the increasing demands. Particularly, the low specific capacity of cathode materials is currently limiting the energy storage capability of LIBs. Vanadium pentoxide (V2O5) has been an emerging cathode material owing to its low cost, high electrode potential in lithium-extracted state (up to 4.0 V), and high specific capacities of 294 mAh g-1 (for a 2 Li+/V2O5 insertion process) and 441 mAh g-1 (for a 3 Li+/V2O5 insertion process). Furthermore, to enhance the power rate capability of LIBs core-shell materials have been investigated to overcome the low electrical conductivity and small Li+ diffusion coefficients of cathode materials. Here we demonstrate an approach to achieving stable 2 and 3 Li+ insertion into amorphous V2O5 shells conformally deposited on electrospun carbon nanofiber networks (30-50 nm in shell thickness) via pulsed electrodeposition. Capacities of 291 and 429 mAh g-1 were achieved in the voltage ranges of 4.0 – 2.0 and 4.0 – 1.5 V (vs. Li/Li+) respectively, which are in good agreement with corresponding theoretical values of 294 mAh g-1 for 2 Li+/V2O5 insertion and 441 mAh g-1 for 3 Li+/V2O5 insertion into crystalline V2O5 materials. Moreover, after 100 cycles, capacity retention values of 97% and 70% were achieved for 2 Li+/V2O5 and 3 Li+/V2O5 insertion, respectively. Such hybrid materials are promising as high-capacity flexible electrodes for future LIBs.

Highly stable two and three lithium insertion in amorphous V2O5 shells coaxially deposited on electrospun carbon nanofibers: A self-supported membrane for high-capacity lithium ion battery cathodes

255th National Meeting (2018)

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