摘要
废旧正极材料是废旧锂离子电池回收利用的重点。以废旧LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)为研究对象,在不预先脱除导电碳和聚偏氟乙烯(PVDF)杂质的情况下,采用高温固相直接再生制备电化学性能优良的再生正极材料。通过XRD、SEM、CV、EIS等分析方法和恒电流充放电技术研究补锂比x(x为废旧NCM523与LiOH的物质的量比)对直接再生NCM523结构及性能的影响。结果表明,随着补锂比的增加,再生的NCM523层状结构有序度先增加后减小,氧化还原反应可逆程度、CEI膜阻抗和电荷转移阻抗先减小后增加,锂离子扩散系数先增加后减小,再生NCM523的放电比容量呈现先上升后下降的趋势。在补锂比x为0.75时,再生的NCM523具有最佳的有序层状结构,其0.1C倍率时首次库伦效率为83.87%、放电比容量为148.2 mA·h/g,1.0C倍率时初始放电比容量为139.5 mA·h/g、循环100次后容量保持率为80.18%。EIS及CV测试也表明,在该条件下再生的样品具有较佳结构稳定性和离子导电率。作为对照,经预烧脱除导电碳黑和PVDF的废旧NCM523经高温固相直接再生后,0.1C倍率时首次放电比容量为145.0 mA·h/g,库伦效率为79.38%,1.0C倍率时放电比容量为123.5 mA·h/g,循环100次后容量保持率为62.29%。研究结果为废旧正极材料回收利用提供新思路。
The focus of recycling of waste lithium⁃ion batteries is spent cathode materials.In this paper,Spent LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)was directly generated by a high⁃temperature solid⁃phase reaction method,in which the con⁃ductive carbon and the polyvinylidene fluoride binder were not removed.The effects of lithium supplementation(x was de⁃fined as the mole ratio of NCM523 and LiOH)on the structure and performance of the regenerated NCM523 were investi⁃gated by XRD,SEM,CV,EIS,and galvanostatic charging/discharging techniques.As the lithium supplementation in⁃creased,the layered structure ordering degree,lithium ion diffusion coefficient,and capacity of the regenerated NCM523 ex⁃hibited an initial increase,followed by a subsequent decrease.Concurrently,the redox reaction reversibility,CEI membrane impedance,and charge transfer impedance demonstrated an initial decrease,followed by an increase.The optimal layered structure of the regenerated NCM523 was observed at a lithium replenishment x of 0.75.The regenerated NCM523 exhibited an initial coulombic efficiency of 83.87%,accompanied by a discharge specific capacity of 148.2 mA·h/g at 0.1C.Addition⁃ally,it demonstrated an initial capacity of 139.5 mA·h/g at 1.0C,along with a retention rate of 80.18%after 100 cycles.Fur⁃thermore,the use of EIS and CV tests demonstrated that the regenerated samples exhibited enhanced structural stability ionic conductivity.As a comparison,the discarded NCM523 pretreated with calcination to remove conductive carbon and PVDF after regenerating by using high⁃temperature solid⁃phase direct regeneration exhibited a first⁃cycle discharge ca⁃pacity of 145.0 mA·h/g at 0.1C,with a coulombic efficiency of 79.38%.Its discharge capacity at 1.0C was 123.5 mA·h/g,maintaining 62.29%after 100 cycles.The findings of this study offered novel approaches for the recycling of waste cathode materials.
作者
罗炳鑫
吴娅妮
刘真珍
陈筱盼
潘吴雪
王玉莹
周冬玲
文衍宣
LUO Bingxin;WU Yani;LIU Zhenzhen;CHEN Xiaopan;PAN Wuxue;WANG Yuying;ZHOU Dongling;WEN Yanxuan(School of Chemistry and Chemical Engineering,Guangxi University,Nanning 530004,China)
出处
《无机盐工业》
北大核心
2025年第12期26-33,共8页
Inorganic Chemicals Industry
基金
广西大学大学生创新训练项目(S202310593364)。
关键词
废旧锂离子电池
废旧正极材料
直接再生
高温固相法
spent lithium⁃ion batteries
spent cathode materials
direct regeneration
high⁃temperature solid⁃phase method
