| 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 | |
| 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 | |
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| 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. | |
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