Li batteries with anion-redox cathode such as Lithium-Sulfur and Lithium-“solid oxygen” chemistries share a lot of common features. In this talk I will discuss the roles of soluble redox mediators in electrolyte, and various strategies to improve the cycle life of Lithium metal anode. I will also address Lithium-matched full-cell performance. Especially, the new “solid oxygen” anion-redox cathode, with an amorphous Li2O/Li2O2/LiO2 mixture stabilized by interfacial wetting with porous Co3O4, shows a mass density exceeding 2.2g/cm3 and a discharge capacity of 587 Ah/kg at 2.55 V vs. Li/Li+, with a very stable cycling performance in EC/DEC electrolyte (only 1.8% capacity loss after 130 cycles in lithium-matched full-cell tests against Li4Ti5O12 anode). The cathode shows round-trip overpotential loss of only 0.24 V, a five-fold improvement compared to gas-evolving Li-air battery. Moreover, the cathode is automatically protected from O2 gas release through shuttling of superoxoradical species in carbonate electrolytes, which shunts the voltage to below 2.95 V however overcharged.

Anion-redox batteries and lithium metal protection

253rd National Meeting (2017)

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