Hanwei Zhang,Xiaoyun Zhang,Tianyi Zeng,Aichun Dou,Panpan Zhang,Mingru Su,Yu Zhou,Yunjian Liu
The application of Ni-rich ternary cathode materials is restricted by the irreversible phase transition and interfacial side reactions during long-term cycling. Herein, a LiTaO 3 coating and Ta 5+ doping strategy are simultaneously achieved by a simple solid-phase synthesis. The surface side-reaction and undesired phase transition of LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) are effectively restrained by this approach, which utilizes residual lithium to afford the coating. The NCA-LTO 3 (The modified NCA with a LiTaO 3 coating content of 3 wt%) delivers a high reversible capacity of 168.04 at 5 C (140.56 mAh g −1 for NCA), revealing the enhanced rate capability. More importantly, the cycling life could be greatly maintained after 200 cycles with a significant capacity retention of 94.1% (61.2% for NCA) at 1 C. Mechanism analysis indicates that such improvement is ascribed to the coating of conductor LiTaO 3 and doping Ta 5+ greatly promoting the Li-ion diffusion and stabilizing the interface of NCA. The study proposes a highly convenient strategy for interfacial optimization of cathode materials toward assisting the large-scale production of high-performance NCA.
Mengting Si,Dandan Wang,Rui Zhao,Du Pan,Chen Zhang,Caiyan Yu,Xia Lu,Huiling Zhao,Ying Bai
As one of the most promising cathodes for next-generation lithium ion batteries (LIBs), Li-rich materials have been extensively investigated for their high energy densities. However, the practical application of Li-rich cathodes is extremely retarded by the sluggish electrode–electrolyte interface kinetics and structure instability. In this context, piezoelectric LiTaO 3 is employed to functionalize the surface of Li 1.2 Ni 0.17 Mn 0.56 Co 0.07 O 2 (LNMCO), aiming to boost the interfacial Li + transport process in LIBs. The results demonstrate that the 2 wt% LiTaO 3 -LNMCO electrode exhibits a stable capacity of 209.2 mAh g −1 at 0.1 C after 200 cycles and 172.4 mAh g −1 at 3 C. Further investigation reveals that such superior electrochemical performances of the LiTaO 3 modified electrode results from the additional driving force from the piezoelectric LiTaO 3 layer in promoting Li + diffusion at the interface, as well as the stabilized bulk structure of LNMCO. The supplemented LiTaO 3 layer on the LNMCO surface herein, sheds new light on the development of better Li-rich cathodes toward high energy density applications.
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