All-inorganic nitrate electrolyte for high-performance lithium oxygen battery

Lithium-oxygen (Li-O₂) batteries have been regarded as an expectant successor for next-generation energy storage systems owing to their ultra-high theoretical energy density. However, the comprehensive properties of the commonly utilized organic salt electrolyte are still unsatisfactory, not to mention their expensive prices, which seriously hinders the practical production and application of Li-O₂ batteries. Herein, we have proposed a low-cost all-inorganic nitrate electrolyte (LiNO₃−KNO₃−DMSO) for Li-O₂ batteries. The inorganic nitrate electrolyte exhibits higher ionic conductivity and a wider electrochemical stability window than the organic salt electrolyte. The existence of K⁺ can stabilize the O₂⁻ intermediate, promoting the discharge process through the solution pathway with an enlarged capacity. Even at an ultra-low concentration of 0.01 M, the K⁺ can still remain stable to promote the solution discharge process and also possess a new function of inhibiting the dendrite growth by electrostatic shielding, further enhancing the battery stability and contributing to the long cycle lifetime. As a result, in the 0.99 M LiNO₃−0.01 M KNO₃−DMSO electrolyte, the Li-O₂ batteries exhibit prolonged cycling performance (108 cycles) and excellent rate performance (2 A·g⁻¹), significantly superior to the organic salt one.