Local Electric‐Field‐Driven Fast Li Diffusion Kinetics at the Piezoelectric LiTaO3 Modified Li‐Rich Cathode–Electrolyte Interphase

• Published in: Advanced science Vol. 7; no. 3; pp. 1902538 - n/a
• Main Authors: Si, Mengting, Wang, Dandan, Zhao, Rui, Pan, Du, Zhang, Chen, Yu, Caiyan, Lu, Xia, Zhao, Huiling, Bai, Ying
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley and Sons Inc 01.02.2020; Wiley
• Subjects: electrochemical performance; interfacial engineering; lithium ion batteries (LIBs); Li‐rich cathodes; piezoelectric LiTaO3 coating layer
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.201902538

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 LiTaO3 is employed to functionalize the surface of Li1.2Ni0.17Mn0.56Co0.07O2 (LNMCO), aiming to boost the interfacial Li+ transport process in LIBs. The results demonstrate that the 2 wt% LiTaO3‐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 LiTaO3 modified electrode results from the additional driving force from the piezoelectric LiTaO3 layer in promoting Li+ diffusion at the interface, as well as the stabilized bulk structure of LNMCO. The supplemented LiTaO3 layer on the LNMCO surface herein, sheds new light on the development of better Li‐rich cathodes toward high energy density applications. The decorated LiTaO3 with intrinsic characteristic of stress response at the surface of active LNMCO induces a local electric field, which significantly promotes Li+ diffusion at the cathode–electrolyte interphase, particularly in the discharge process. The application of the “initiative” function interphase material herein contributes to the comprehension of interphase engineering in a broad range of applications in the electrochemical and energy conversion community.