Pushing the Theoretical Limit of Li-CFx Batteries: A Tale of Bifunctional Electrolyte

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• 作者：Ezhiylmurugan Rangasamy ; Juchuan Li ; Gayatri Sahu ; Nancy Dudney ; Chengdu Liang
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：May 14, 2014
• 年：2014
• 卷：136
• 期：19
• 页码：6874-6877
• 全文大小：271K
• 年卷期：v.136,no.19(May 14, 2014)
• ISSN：1520-5126

文摘

In a typical battery, the inert electrolyte functions solely as the ionic conductor without contribution to the cell capacity. Here we demonstrate that the most energy-dense Li-CF_x battery delivers a capacity exceeding the theoretical maximum of CF_x with a solid electrolyte of Li₃PS₄ (LPS) that has dual functions: as the inert electrolyte at the anode and the active component at the cathode. Such a bifunctional electrolyte reconciles both inert and active characteristics through a synergistic discharge mechanism of CF_x and LPS. The synergy at the cathode is through LiF, the discharge product of CF_x, which activates the electrochemical discharge of LPS at a close electrochemical potential of CF_x. Therefore, the solid-state Li-CF_x batteries output 126.6% energy beyond their theoretic limits without compromising the stability of the cell voltage. The additional energy comes from the electrochemical discharge of LPS, the inert electrolyte. This bifunctional electrolyte revolutionizes the concept of conventional batteries and opens a new avenue for the design of batteries with unprecedented energy density.