The Role of Current Collector Corrosion on the Performance of Thermal Batteries

Abstract

As a bridge connecting external circuits and electrodes, current collectors are critical for battery performance. While numerous studies have investigated lithium-ion battery current collectors at room temperature, fewer address high-temperature batteries (>500 °C). The interfacial properties of thermal battery collector and cathode at high temperatures remain unclear, and collector selection is more empirical. In this paper, the effects of 304 stainless steel on the discharge performance of NiS2 cathode were investigated. At 500 °C, 100 mA cm−2 and 1.5 V cutoff voltage, NiS2 first-voltage plateau specific capacity with 304 stainless steel current collector exhibits a high specific capacity of 320 mAh g−1 and total specific capacity of 700 mAh g−1, 146% and 17% higher than Ni, respectively. The Ni current collector of the thermal battery underwent severe chemical reactions at high operating temperatures, consuming active mass and increasing interfacial impedance. In contrast, stainless steel formed an iron-chromium sulfide passivation layer inhibiting further chemical reactions and accelerating charge transfer rate at the interface, resulting in effective increase in the discharge capacity of the thermal battery. This study provides theoretical guidance for selecting current collectors for thermal batteries based on high-temperature chemical reactions.