Realizing Complete Solid‐Solution Reaction in High Sodium Content P2‐Type Cathode for High‐Performance Sodium‐Ion Batteries. (9th July 2020)

• Record Type: Journal Article
• Authors: Jin, Ting; Wang, Peng‐Fei; Wang, Qin‐Chao; Zhu, Kunjie; Deng, Tao; Zhang, Jiaxun; Zhang, Wei; Yang, Xiao‐Qing; Jiao, Lifang; Wang, Chunsheng
• Is Part Of: Angewandte Chemie. Volume 132:Number 34(2020)
• Page Start: 14619
• Page End: 14624
• Publication Date: 2020-07-09
• Subjects: batteries -- electrochemistry -- materials chemistry -- sodium -- structure elucidation; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202003972
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: P2‐type layered oxides suffer from an ordered Na + /vacancy arrangement and P2→O2/OP4 phase transitions, leading them to exhibit multiple voltage plateaus upon Na + extraction/insertion. The deficient sodium in the P2‐type cathode easily induces the bad structural stability at deep desodiation states and limited reversible capacity during Na + de/insertion. These drawbacks cause poor rate capability and fast capacity decay in most P2‐type layered oxides. To address these challenges, a novel high sodium content (0.85) and plateau‐free P2‐type cathode‐Na0.85 Li0.12 Ni0.22 Mn0.66 O2 (P2‐NLNMO) was developed. The complete solid‐solution reaction over a wide voltage range ensures both fast Na + mobility (10 −11 to 10 −10 cm 2 s −1 ) and small volume variation (1.7 %). The high sodium content P2‐NLNMO exhibits a higher reversible capacity of 123.4 mA h g −1, superior rate capability of 79.3 mA h g −1 at 20 C, and 85.4 % capacity retention after 500 cycles at 5 C. The sufficient Na and complete solid‐solution reaction are critical to realizing high‐performance P2‐type cathodes for sodium‐ion batteries. Abstract : A high sodium content (0.85) and plateau‐free P2‐type cathode, Na0.85 Li0.12 Ni0.22 Mn0.66 O2, is developed for sodium‐ion batteries. The sodium content promises a large specific capacity of 123.4 mA h g −1 with an average working voltage as high as 3.5 V. The complete solid‐solution reaction over a wide voltage range ensures small volume variation (1.7 %) and fast Na + kinetics (10 −10 to 10 −11 cm 2 s −1 ), contributing to both excellent cycling stability and rate capability.