微量Mg/F表面梯度渗透改善高电压LiCoO2界面脆弱
Enhancement of the fragile interface of high voltage LiCoO2 by surface gradient permeation of trace amounts of Mg/F
作者单位E-mail
王鑫龙 电子科技大学材料与能源学院, 成都 611731  
程真国 电子科技大学材料与能源学院, 成都 611731  
王果 电子科技大学材料与能源学院, 成都 611731  
张晓琨 电子科技大学材料与能源学院, 成都 611731  
向勇 电子科技大学材料与能源学院, 成都 611731  
王欣全 电子科技大学材料与能源学院, 成都 611731 wangxinquan@uestc.edu.cn 
摘要: 采用高温固相法在1 050℃下烧结,制备了LiCoO2低浓度梯度改性样品,分别为LiF掺杂包覆(LCOLF、LCO@LF)和MgF2掺杂包覆(LCOMF、LCO@MF)。通过光电子能谱、透射电子显微镜和电化学技术等表征方法,对比分析材料形貌及电化学性能。结果表明,体相掺杂复合电极中,LCOLF热重测试显示出最优热稳定性,LCOMF晶体中(003)和(104)晶面间距收缩;45℃下1C倍率循环70圈后,LCOLF和LCOMF比容量分别为141.45和166.98 mAh·g-1,循环性能优于LiCoO2。表面包覆复合电极中,LCO@LF和LCO@MF晶粒表面光洁且晶格氧键价都向更高结合能方向增强;LCO@MF构建了坚实且紧密的包覆层,循环70圈后,放电比容量和容量保持率分别为183 mAh·g-1和91.26%(LCO@LF分别为154.38 mAh·g-1和77.54%),循环性能显著优于体相掺杂。
关键词: LiCoO2  体相掺杂  表面包覆  LiF  MgF2  梯度渗透
基金项目: 四川省科学技术厅项目(No.2022ZYD0130)、成都高新技术产业开发区科技和人才工作局项目(No.2069998)资助。
Abstract: Low-concentration gradient-modified samples of LiCoO2 were prepared by sintering at 1 050℃ using high-temperature solid-phase method, and were coated with LiF doping (LCOLF, LCO@LF) and MgF2 doping (LCOMF, LCO@MF). The material morphologies and electrochemical properties were compared and analyzed utilizing characterization tests such as X-ray photoelectron spectroscopy, transmission electron microscopy, and electrochemical techniques. The results show that in bulk-doping composite electrodes, the thermogravimetric test demonstrated that LCOLF had optimal thermal stability. In LCOMF crystals, crystal plane spacing of (003) and (104) contracted; after 70 cycles at 1C rate under 45℃, the specific capacities of LCOLF and LCOMF were 141.45 and 166.98 mAh·g-1 respectively, and their cycling performance was superior to that of the LiCoO2. In the surface-coated composite electrodes, LCO@LF and LCO@MF grains had clean surfaces and the bond valence of lattice oxygen was enhanced toward higher binding energy; LCO@MF built a solid and compact coating layer, and the specific capacity and capacity retention after 70 cycles were 183 mAh·g-1 and 91.26% (that of LCO@LF were respectively 154.38 mAh·g-1 and 77.54%). The cycling performance of surface-coated composite electrodes was significantly better than that of bulk-doping composite electrodes.
Keywords: LiCoO2  bulk doping  surface coating  LiF  MgF2  gradient infiltration
投稿时间:2023-07-10 修订日期:2024-01-09
摘要点击次数:  512
全文下载次数:  189
王鑫龙,程真国,王果,张晓琨,向勇,王欣全.微量Mg/F表面梯度渗透改善高电压LiCoO2界面脆弱[J].无机化学学报,2024,40(3):571-580.
查看全文  查看/发表评论  下载PDF阅读器
Support information: