Enhancement the discharge capacity of NiCl2-xBrx thermal battery by inhibition overflow of electrolyte

Abstract

Nickel chloride is a promising cathode material for high-power thermal batteries due to its high theoretical capacity, high discharge current density, and high electrode potential. Nevertheless, its substandard electrical conductivity, elevated-temperature melting properties, and electrolyte interface instability considerably constrain its practical applications. In this paper, NiCl_1.6Br_0.4 with high electrical conductivity and high specific capacity was prepared through comparative experiments, and the merits of BN over MgO for LiB/NiCl_1.6Br_0.4 thermal battery system were demonstrated by analyzing the difference between electrochemical performance and melting leaching phenomenon. The LiB/BN-E/NiCl_2-xBr_x thermal battery system demonstrates optimal discharge performance at 500 °C, achieving a specific capacity of 319 mAh g⁻¹, a specific energy of 744 Wh kg⁻¹, and a specific power of 7.0 kW kg⁻¹ under a discharge condition of 0.2 A cm⁻². The LiB/BN-E/NiCl_2-xBr_x thermal battery system has application prospects in high-energy thermal batteries.