Interface optimization and fast ion exchange route construction in CoS2 electrode by decorated with dielectric Al2O3 nanoparticles for high temperature primary lithium batteries

Abstract As the most investigated cathode of thermal batteries, the electrochemical performance of CoS2 is limited by a big polarization at high current density and low working temperature, which is ascribed to the poor wettability of molten salt on CoS2 surface and low exchange current density. In this contribution, Al2O3 is selected as a modifier to improve the wettability of molten salt on CoS2 surface and exchange current density at the same time, by adjusting the dielectric polarization field of CoS2 surface. The discharge capacity (V ≥ 1.7 V) of CoS2 increases by ~11% at 500 °C with a discharge current of 300 mA cm−2, and 55% at 450 °C with a discharge current of 100 mA cm−2, by the decoration of Al2O3 nanoparticles. Moreover, the influence of decorated Al2O3 nanoparticles on the electrochemical performance of CoS2 are discussed.