Quantitative investigation of the gassing behavior in cylindrical Li 4 Ti 5 O 12 batteries
Quantitative investigation of the gassing behavior in cylindrical Li 4 Ti 5 O 12 batteries
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DOI：
10.1016/j.jpowsour.2017.01.073
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发表时间：
2017-03
影响因子：
9.2
通讯作者：
Qian Wang-;Jian Zhang;Wei Liu;Xiaohua Xie;B. Xia
中科院分区：
文献类型：
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作者：
Qian Wang-;Jian Zhang;Wei Liu;Xiaohua Xie;B. Xia
Li4Ti5O12的放气行为是锂离子电池应用的一个关键限制。电极/电解液界面的影响以及放气过程中涉及的潜在机制仍然存在争议。本文利用自行设计的压力测试装置，研究了18650圆柱形Li4Ti5O12电池内压的定量演化过程。结果表明，内压在形成周期内显著增加，并在随后的周期中继续增长。经过几次充放电循环后，压力最终达到恒定。同时，还研究了固体电解质界面(SEI)膜的形成。结果表明，初始形成的SEI膜的厚度为24 nm，并且在随后的循环中观察到收缩。此外，随着压力的升高，厚度没有明显增加。这些对比研究揭示了放气行为的一种可能机制。我们认为，放气行为与副反应有关，副反应由Li4Ti5O12电极的电位决定，其中电极/电解液界面的活性位置控制着反应的程度。
The Li4Ti5O12gassing behavior is a critical limitation for applications in lithium-ion batteries. The impact of electrode/electrolyte interface, as well as the underlying mechanisms involved during the gassing process, are still debated. Herein, a quantitative evolution of the internal pressure in 18650-type cylindrical Li4Ti5O12batteries is investigated using a self-designed pressure testing device. The results indicate that the internal pressure significantly increases during the formation cycle and continues growing during the following cycles. After several charge and discharge cycles, the pressure finally reaches constant. Simultaneously, the formation of the solid electrolyte interphase (SEI) film is also investigated. The results suggest that the initial formed SEI film has a thickness of 24 nm, and is observed to shrink during the following cycles. Furthermore, no apparent increase in thickness accompanying the pressure rising is noticed. These comparative investigations reveal a possible mechanism of the gassing behavior. We suggest that the gassing behavior is associated with side reactions which are determined by the potential of the Li4Ti5O12electrode, where the active sites of the electrode/electrolyte interface manage the extent of the reaction.