Weakly-solvating electrolytes enable ultralow-temperature (-80 °C) and high-power CFx/Li primary batteries

Fluorinated carbons (CFx)/Li primary batteries with high theoretical energy density have been applied as indispensable energy storage devices with no need for rechargeability, yet plagued by poor rate capability and narrow temperature adaptability in actual scenarios. Herein, benefiting from precise solvation engineering for synergistic coordination of anions and low-affinity solvents, the optimized cyclic ether-based electrolyte is elaborated to significantly facilitate overall reaction dynamics closely correlated to lower desolvation barrier. As a result, the excellent rate (15 C, 650 mAh g(-1)) at room-temperature and ultra-low-temperature performance dropping to -80 degrees C (495 mAh g(-1) at average output voltage of 2.11 V) is delivered by the end of 1.5 V cut-off voltage, far superior to other organic liquid electrolytes. Furthermore, the CFx/Li cell employing the high-loading electrode (18-22 mg cm(-2)) still yields 1,683 and 1,395 Wh kg(-1) in the case of -40 degrees C and -60 degrees C, respectively. In short, the novel design strategy for cyclic ethers as basic solvents is proposed to enable the CFx/Li battery with superb subzero performances, which shows great potential in practical application for extreme environments.

Automated summary

By employing precise solvation engineering, an optimized cyclic ether-based electrolyte is used to enhance the rate capability and low-temperature adaptability of CFx/Li primary batteries. At room temperature, the battery exhibits excellent rate capability (15 C, 650 mAh g(-1)) and at -80 degrees C, it achieves a performance of 495 mAh g(-1) at an average output voltage of 2.11 V. Moreover, even with high-loading electrode (-40 degrees C and -60 degrees C), the battery still delivers energy densities of 1,683 Wh kg(-1) and 1,395 Wh kg(-1) respectively. This novel design strategy of using cyclic ethers as solvents shows great potential for practical application in extreme environments.