Promising Cell Configuration for Next-Generation Energy Storage: Li2S/Graphite Battery Enabled by a Solvate Ionic Liquid Electrolyte

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• 作者：Zhe Li ; Shiguo Zhang ; Shoshi Terada ; Xiaofeng Ma ; Kohei Ikeda ; Yutaro Kamei ; Ce Zhang ; Kaoru Dokko ; Masayoshi Watanabe
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：June 29, 2016
• 年：2016
• 卷：8
• 期：25
• 页码：16053-16062
• 全文大小：638K
• 年卷期：0
• ISSN：1944-8252

文摘

Lithium-ion sulfur batteries with a [graphite|solvate ionic liquid electrolyte|lithium sulfide (Li₂S)] structure are developed to realize high performance batteries without the issue of lithium anode. Li₂S has recently emerged as a promising cathode material, due to its high theoretical specific capacity of 1166 mAh/g and its great potential in the development of lithium-ion sulfur batteries with a lithium-free anode such as graphite. Unfortunately, the electrochemical Li⁺ intercalation/deintercalation in graphite is highly electrolyte-selective: whereas the process works well in the carbonate electrolytes inherited from Li-ion batteries, it cannot take place in the ether electrolytes commonly used for Li–S batteries, because the cointercalation of the solvent destroys the crystalline structure of graphite. Thus, only very few studies have focused on graphite-based Li–S full cells. In this work, simple graphite-based Li–S full cells were fabricated employing electrolytes beyond the conventional carbonates, in combination with highly loaded Li₂S/graphene composite cathodes (Li₂S loading: 2.2 mg/cm²). In particular, solvate ionic liquids can act as a single-phase electrolyte simultaneously compatible with both the Li₂S cathode and the graphite anode and can further improve the battery performance by suppressing the shuttle effect. Consequently, these lithium-ion sulfur batteries show a stable and reversible charge–discharge behavior, along with a very high Coulombic efficiency.