| Reaction Behavior of Li4+xTi5O12 Anode Material as Depth of Discharge |
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Woo-Suk Cho, Jun-Ho Song, Min-Sik Park, Jae-Hun Kim, Jeom-Soo Kim, Young-Jun Kim |
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Advanced Batteries Research Center, Korea Electronics Technology Institute;Advanced Batteries Research Center, Korea Electronics Technology Institute;Advanced Batteries Research Center, Korea Electronics Technology Institute;Advanced Batteries Research Center, Korea Electronics Technology Institute;Advanced Batteries Research Center, Korea Electronics Technology Institute;Advanced Batteries Research Center, Korea Electronics Technology Institute; |
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| Abstract |
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We have studied the origin of an additional plateau of $Li_{4+x}Ti_5O_{12}$ (LTO) observed at 0.7 V (vs. Li/$Li^+$). Some LTO has to be discharged down to below 1.0 V forming two-stage plateau (1.5 V and 0.7 V) in order to obtain most of capacity while others could achieve the same level of capacity at higher potential (1.0 V vs. Li/$Li^+$) forming one plateau (1.5 V). The particle size effect has been investigated as a possible reason of this. The 0.7 V plateau was gradually elongated with increasing the particle size. The structural variations and kinetic behaviors during discharge were carefully examined by in-situ XRD technique and OCV measurement. According to structural and electrochemical verifications, the kinetic limitation of $Li^+$ insertion is responsible primarily for the two-stage plateau which is related to the particle size of LTO rather than the formation of new intermediate phase during discharge. Herein, we propose a possible reaction model to elucidate this abnormal behavior of LTO below 1.0 V (Li/$Li^+$). |
| Keywords:
Li-ion batteries, Lithium titanate, Spinel, in-situ XRD, Biphasic reaction |
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