Li(V0.5Ti0.5)S2 as a 1 V lithium intercalation electrode.
Li(V0.5Ti0.5)S2 as a 1 V lithium intercalation electrode.
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DOI：
10.1038/ncomms10898
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发表时间：
2016-03-21
影响因子：
16.6
通讯作者：
Bruce PG
中科院分区：
文献类型：
--
作者：
Clark SJ;Wang D;Armstrong AR;Bruce PG
石墨是可充电锂电池的主要负极，其工作电压为∼0.1 V，而不是Li+/Li，可能导致在石墨表面镀锂，这引发了安全问题。钛酸盐，例如Li4Ti5O12，在∼1.6 V时嵌入锂，而不是Li+/Li，以降低电池电压为代价避免有问题的锂电镀。人们对1 V的阳极很感兴趣，因为这一电压足够高，可以避免电镀锂，同时不会显著降低电池电位。硫化物LiVS_2和LiTiS_2已被研究为1 V的插入电极，但存在容量衰减、大的第一循环不可逆容量或极化。本文报道了50/50固溶体Li1+x(V0.5Ti0.5)S2的可逆容量为220mAhg−1(在0.9 V时)，在C/2速率下存储99%的理论电荷，在C速率下保留205mAhg −1(理论上的92%)。速率性能优异，在3C时为200 mAhg−1。放电速度为1 h，极化低，C/2时为100 mV。据我们所知，Li(V0.5Ti0.5)S2的性能/性能超过了以往所有的1 V电极。硫化锂此前曾被研究为锂离子电池的1 V阳极，但存在严重的性能问题。本文报道了一种性能显著的1 V硫化锂电极，表明硫化锂电极有进一步的开发价值。
Graphite, the dominant anode in rechargeable lithium batteries, operates at ∼0.1 V versus Li+/Li and can result in lithium plating on the graphite surface, raising safety concerns. Titanates, for example, Li4Ti5O12, intercalate lithium at∼1.6 V versus Li+/Li, avoiding problematic lithium plating at the expense of reduced cell voltage. There is interest in 1 V anodes, as this voltage is sufficiently high to avoid lithium plating while not significantly reducing cell potential. The sulfides, LiVS2 and LiTiS2, have been investigated as possible 1 V intercalation electrodes but suffer from capacity fading, large 1st cycle irreversible capacity or polarization. Here we report that the 50/50 solid solution, Li1+x(V0.5Ti0.5)S2, delivers a reversible capacity to store charge of 220 mAhg−1 (at 0.9 V), 99% of theoretical, at a rate of C/2, retaining 205 mAhg−1 at C-rate (92% of theoretical). Rate capability is excellent with 200 mAhg−1 at 3C. C-rate is discharge in 1 h. Polarization is low, 100 mV at C/2. To the best of our knowledge, the properties/performances of Li(V0.5Ti0.5)S2 exceed all previous 1 V electrodes. Lithium sulfides have been previously investigated as 1 V anodes for Li-ion batteries, but suffered from significant performance issues. Here, the authors report on a 1 V lithium sulfide electrode with noteworthy performance, demonstrating that sulfide-based electrodes may merit further exploration.