Flexible, self-assembly NiS2/C thin film cathodes for long life thermal battery

Abstract

Thin film cathode with both high utilization and specific capacity is regarded as a promising electrode of long life and miniaturized thermal battery. However, complex synthesis process and a strict size of active materials with nanometer and homogeneity restrict its commercialization. Herein, flexible and self-assembly NiS 2 /C thin film electrodes are built on carbon fiber cloth (NiS 2 /C@CF) base on an in situ synthesize method. The carbon cloth is served as current collector and storage site. The pyrolytic carbon acts both as binder and conductive additive. The uniform and continuous NiS 2 /C@CF thin film is obtained with carbon content of about 5 wt%. Hence, NiS 2 /C@CF thin film cathodes reveal excellent discharge performances that discharge voltage with 1.94–1.75 V and corresponding specific capacity with 1663.0 mAh g −1 in 30 mA cm −2 at 500 °C, the pulse voltage with 2.25–2.0 V and capacity with 1063 mAh g −1 in a pulse current (25 mA cm −2 /100 s---100 mA cm −2 /1 s). The initial study shows that F − of all-Li electrolyte would increase storage capacity of carbon cloth in NiS 2 /C@CF thin film cathodes. The simple method, flexible, processable and high specific capacity make NiS 2 /C@CF thin film electrode more suitable for large-scale applications. • Flexible, self-assembly NiS 2 /C thin film cathodes were successfully synthesized. • Optimal pyrolytic carbon content of continuous NiS 2 /C thin film is confirmed. • Ultra-high specific capacity and stable voltage are exhibited in thermal battery. • All-Li electrolyte proved to increase specific capacity of carbon cloth cathodes.