Reversible Mn2+/Mn4+ double redox in lithium-excess cathode materials
Reversible Mn2+/Mn4+ double redox in lithium-excess cathode materials
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DOI：
10.1038/s41586-018-0015-4
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发表时间：
2018-04-12
期刊：
影响因子：
64.8
通讯作者：
Ceder, Gerbrand
中科院分区：
文献类型：
--
作者：
Lee, Jinhyuk;Kitchaev, Daniil A.;Ceder, Gerbrand
迫切需要低成本、资源友好、高能量密度的锂离子电池正极材料，以满足快速增长的电能储存需求。为了替代镍和钴（其是有限的资源并且与安全问题相关），在当前的锂离子电池中，基于锰的高容量阴极将是特别期望的，这是由于该金属的低成本和高丰度以及Mn 4+氧化态的固有稳定性。在这里，我们提出了一种结合高价阳离子和氟部分取代无序岩盐结构中的氧的策略，将可逆的Mn 2 +/Mn 4+双氧化还原对纳入锂过量的阴极材料。由此生产的富锂阴极具有高容量和能量密度。Mn 2 +/Mn 4+氧化还原的使用降低了氧的氧化还原活性，从而稳定了材料，并为设计用于先进锂离子电池的高性能富锰阴极开辟了新的机会。
There is an urgent need for low-cost, resource-friendly, high-energy-density cathode materials for lithium-ion batteries to satisfy the rapidly increasing need for electrical energy storage. To replace the nickel and cobalt, which are limited resources and are associated with safety problems, in current lithium-ion batteries, high-capacity cathodes based on manganese would be particularly desirable owing to the low cost and high abundance of the metal, and the intrinsic stability of the Mn4+ oxidation state. Here we present a strategy of combining high-valent cations and the partial substitution of fluorine for oxygen in a disordered-rocksalt structure to incorporate the reversible Mn2+/Mn4+ double redox couple into lithium-excess cathode materials. The lithium-rich cathodes thus produced have high capacity and energy density. The use of the Mn2+/Mn4+ redox reduces oxygen redox activity, thereby stabilizing the materials, and opens up new opportunities for the design of high-performance manganese-rich cathodes for advanced lithium-ion batteries.