High-temperature ultrafast welding creating favorable V2O5 and conductive agents interface for high specific energy thermal batteries

Abstract

The high interfacial resistance between V 2 O 5 cathode materials and conductive agents (molten salt and super carbon) is one of the biggest issues that hinder the development of high specific energy thermal batteries. Designing fast Li + and e – transport channels in cathode electrodes is considered as an effect method to improve electrochemical performance. Hence, a high-temperature ultrafast welding is proposed to reduce V 2 O 5 /conductive agents interfacial resistance by reconstructing the transmission channels of Li + and e – in this paper. The experimental studies reveal the optimum ultrafast welding of 700 °C for 10 s, eliminating gap resistance of cathode electrodes induced by the melt of solid molten salt and rebuilding the more plentiful Li + and e – transport channels, further reducing the contact resistance and gap resistance. Therefore, the electrodes deliver a high specific capacity of 270.69 mAh g −1 and a high specific energy of 610.60 Wh kg −1 at 0.1 A cm −2 and 500 °C with a cut-off voltage of 1.6 V. The high-temperature ultrafast welding provides guidance to build Li + and e – transport channels of other cathode materials in thermal batteries.