HIGH ENERGY ZINC BATTERY SYSTEM WITH AN EXTREMELY WIDE OPERATING TEMPERATURE RANGE

Abstract

Military and planetary application requires high energy density rechargeable battery with an extremely wide operating temperature range. Current rechargeable batteries only operate in a narrow range from -20 ℃ to 60 ℃. Low ionic conductivity of electrolyte and sluggish lithium ion diffusion of electrode at a low temperature, the irreversible phase transition at elevated temperature limit broadening operating temperature range of battery. In this research, a novel zinc battery LiFePO4/Li2ZnCl4.9H2O/Zn with wide operating temperature range between -70 ℃ and 70 ℃ has been developed. The Li2ZnCl4.9H2O electrolyte has very high ionic conductivity at -70 ℃, while the PEDOT coating on LiFePO4 reduce the side reaction at 70 ℃. At 70 ℃, LiFePO4@PEDOT/Li2ZnCl4.9H2O/Zn cells provide a capacity of 130 mAh.g-1 achieved over 20 cycles at 0.3 C, with a high rate capability. It also showed a stable cycling at -70 ℃ with 133 mAh.g-1 for 50 cycles at 0.1 C.