Browsing by Author "Guo, XW"

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    Direct evidence of concurrent solid-solution and two-phase reactions and the nonequilibrium structural eEvolution of LiFePO(4)
    (American Chemical Society, 2012-05-09) Sharma, N; Guo, XW; Du, GD; Guo, ZP; Wang, JZ; Wang, ZX; Peterson, VK
    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. © 2012, American Chemical Society.