采用阳极预锂化技术的锂离子电池高倍率老化容量衰减机理研究

Research on the capacity fading mechanism of high rate aged lithium-ion batteries with anode prelithiation treatment

通过阳极预锂化技术,可以补充锂离子电池在化成以及后续循环过程中活性锂的损失,由此提高锂离子电池的能量密度以及循环寿命。然而阳极预锂化后锂离子电池衰减机理如何变化,一直没有明确的研究结论。本文研究了经阳极预锂化的石墨-磷酸铁锂电池在高倍率老化过程中,充放电电位、电池容量、电池健康状态(SOH)、电化学阻抗等的演变过程,并研究了电池性能衰减过程中正、负极片的表面形貌、晶体结构、热稳定性变化过程。研究结果表明,在一定的补锂量范围内,阳极预锂化技术不影响电池的寿命衰减机理,而是通过克服不可逆活性锂损失来延长电池循环寿命。

The anode prelithiation technology can supplement the loss of active lithium in the activation process and subsequent cycling of lithium-ion batteries,so as to improve the energy density and cycling life of lithium-ion batteries.However,it is still unclear that the decay mechanism of lithium-ion batteries after anode prelithiation.In this work,we studied the evolution of charge/discharge potential,specific capacity,State of Health(SOH)and electrochemical impedance of the Graphite-LiFePO4 battery after high rate aging conditions,the surface morphology,crystal structure and thermal stability of electrodes under fading process were also studied.The results indicate that within a certain range of filling amount of lithium,the anode prelithiation technology extends the battery cycle life by overcoming the irreversible loss of active lithium,rather affecting the battery fading mechanism.