School of Metallurgy and Environment , Central South University , Changsha 410083 , China.
ACS Appl Mater Interfaces. 2018 Aug 15;10(32):27141-27149. doi: 10.1021/acsami.8b10178. Epub 2018 Aug 1.
Overlithiated oxide cathode materials show high capacity but poor cycle stability and voltage attenuation. In this work, a concentration difference driven molten salt ion exchange strategy is used to replace a small quantity of lithium ions by sodium ions. With the entry of sodium ions, the interplanar spacing is increased and the structure is stabilized. The electrochemical properties of materials have been improved obviously. The powder X-ray diffraction, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and transmission electron microscopy are used to detect the entry of sodium ions and structural changes. The modified materials display high discharge specific capacity, excellent cycling performance, and reduced voltage attenuation.
过锂氧化物阴极材料具有高容量，但循环稳定性和电压衰减差。在这项工作中，采用浓度差驱动的熔融盐离子交换策略，用钠离子取代少量的锂离子。随着钠离子的进入，层间距增大，结构得到稳定。材料的电化学性能得到明显改善。采用粉末 X 射线衍射、电感耦合等离子体原子发射光谱、扫描电子显微镜和透射电子显微镜检测钠离子的进入和结构变化。改性材料显示出高放电比容量、优异的循环性能和降低的电压衰减。
