American Chemical Society, Journal of the American Chemical Society, 46(136), p. 16116-16119, 2014
DOI: 10.1021/ja508463z
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We have conducted extensive theoretical and experimental investigations to unravel the origin of the electrochemical properties of hybrid Mg2+/Li+ rechargeable batteries at the atomistic and macroscopic levels. By revealing the thermodynamics of Mg2+ and Li+ co-insertion into the Mo6S8 cathode host using density functional theory calculations, we show that there is a threshold Li+ activity for the pristine Mo6S8 cathode to prefer lithiation instead of magnesiation. By precisely controlling the insertion chemistry using a dual-salt electrolyte, we have enabled ultrafast discharge of our battery by achieving 93.6 % capacity retention at 20 C and 87.5 % at 30 C, respectively, at room temperature.