Potassium iodide as a low-cost cathode material for efficient potassium-ion storage
Potassium iodide as a low-cost cathode material for efficient potassium-ion storage
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DOI：
10.1016/j.ensm.2021.07.025
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发表时间：
2021-10
影响因子：
20.4
通讯作者：
L. Deng;Meiying Feng;Ruiting Wang;Yusi Yang;Xiaogang Niu;Juan Zhang;Lulu Tan;Jianwen Zhang;Yifan Chen;L. Zeng;Yujie Zhu;Lin Guo
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文献类型：
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作者：
L. Deng;Meiying Feng;Ruiting Wang;Yusi Yang;Xiaogang Niu;Juan Zhang;Lulu Tan;Jianwen Zhang;Yifan Chen;L. Zeng;Yujie Zhu;Lin Guo
钾离子电池以其低成本、高能量密度等优点成为极具吸引力的电化学储能技术。目前，报道的kib阴极候选材料都局限于插层型材料。这些材料的工作原理都涉及到体积较大的k离子在离子键合的刚性框架中反复插入-脱插，这往往导致反应动力学缓慢，结构变形不可逆，循环稳定性差。在这里，一种低成本的转换型材料，碘化钾（KI），被提出作为kib的有前途的阴极候选者。结果表明，KI的脱钾-钾化过程是通过溶解-沉淀反应进行的，涉及高可溶性ki3中间体，导致穿梭效应和容量衰减。因此，采用电解液调制与分离器改性相结合的简单策略，有效地提高了KI的电化学性能，在550次循环后，其容量保持率达到了95.5%。本研究为进一步探索新型kib的溶解-沉淀反应机理为基础的高性能电极材料提供了思路。
Potassium-ion batteries (KIBs) are attractive electrochemical energy storage technologies because of their low cost and high energy density. Currently, the reported cathode candidates for KIBs are all limited to the intercalation-type materials. The working principles of these materials all involve the repeated intercalation-deintercalation of bulky K-ions in the ionically-bonded rigid frameworks, which often results in sluggish reaction kinetics, irreversible structural deformation, and poor cycling stability. Here, a low-cost conversion-type material, potassium iodide (KI), is proposed as a promising cathode candidate for KIBs. It is revealed that the depotassiation-potassiation of KI proceedsviaa dissolution-precipitation reaction process involving the highly soluble KI3intermediate, leading to the shuttle effect and capacity decay. Susequently, a simple strategy combining electrolyte modulation with separator modification is adopted to effectively enhance the electrochemical performance of KI, leading to an impressive capacity retention of 95.5% after 550 cycles. The present study may shed some light on further exploration of high-performance electrode materials based on dissolution-precipitation reaction mechanism for the emerging KIBs.