Low temperature performance enhancement of high-safety Lithium–Sulfur battery enabled by synergetic adsorption and catalysis

Abstract The application of lithium-sulfur battery (LSB) is limited by shuttle effect and performance at low temperature. This work investigates the catalytic effect and mechanism for polysulfides conversion by cobalt sulfides/carbon nanotubes (Co3S4@CNT) at low temperature of −25 °C. In order to find out whether the use of catalysts has an impact on safety, thermal runaway behaviors are also explored. For electrochemical performances at −25 °C, the capacity of 1275.6 mAh g−1 is achieved at 0.1 C and the capacity decay rate can be as low as 0.06% at 0.5 C when running 500 cycles. The capacity reaches 941.7 mAh g−1 at 1 C and 858 mAh g−1 even at 2 C. The self-discharge in battery is also relieved. The superior low-temperature performances illustrate the crucial role of catalyst to accelerate reaction kinetics and alleviate shuttle effect. From the perspective of safety, the temperature of thermal runaway occurred in Co3S4@CNT-S button battery is higher than C–S battery. It means Co3S4@CNT can not only accelerate the polysulfides conversion rate and improve the reaction dynamics even at low temperature, but also will not accelerate the occurrence of thermal runaway. These results illustrate that the Co3S4@CNT as sulfur carrier and catalyst play an important role in enhancing the electrochemical performance even at low temperature and improving safety of LSB.