The Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia.
J Am Chem Soc. 2012 May 9;134(18):7867-73. doi: 10.1021/ja301187u. Epub 2012 Apr 30.
Lithium-ion batteries power many portable devices and in the future are likely to play a significant role in sustainable-energy systems for transportation and the electrical grid. LiFePO(4) is a candidate cathode material for second-generation lithium-ion batteries, bringing a high rate capability to this technology. LiFePO(4) functions as a cathode where delithiation occurs via either a solid-solution or a two-phase mechanism, the pathway taken being influenced by sample preparation and electrochemical conditions. The details of the delithiation pathway and the relationship between the two-phase and solid-solution reactions remain controversial. Here we report, using real-time in situ neutron powder diffraction, the simultaneous occurrence of solid-solution and two-phase reactions after deep discharge in nonequilibrium conditions. This work is an example of the experimental investigation of nonequilibrium states in a commercially available LiFePO(4) cathode and reveals the concurrent occurrence of and transition between the solid-solution and two-phase reactions.
锂离子电池为许多便携式设备提供动力，并且在未来很可能在交通运输和电网的可持续能源系统中发挥重要作用。LiFePO(4)是第二代锂离子电池的候选阴极材料，为该技术带来了高倍率性能。LiFePO(4)作为阴极，通过固溶或两相机制发生脱锂，所采用的途径受样品制备和电化学条件的影响。脱锂途径和两相反应与固溶反应之间的关系的细节仍存在争议。在这里，我们使用实时原位中子粉末衍射报告了在非平衡条件下深度放电后固溶和两相反应的同时发生。这项工作是对商业可用 LiFePO(4)阴极中非平衡状态的实验研究的一个例子，揭示了固溶和两相反应的同时发生和转变。
