Boosting fast and durable sodium-ion storage by tailoring well-shaped Na0.44MnO2 nanowires cathode

• Published in: Electrochimica acta 2019-08, Vol.313, p.122-130
• Main Authors: Liu, Yongchang, Liu, Xiaobin, Bu, Fan, Zhao, Xudong, Wang, Lixuan, Shen, Qiuyu, Zhang, Jian, Zhang, Ning, Jiao, Lifang, Fan, Li-Zhen
• Format: Article
• Language: English
• Subjects: Carbon fibers; Cathode; Cathodes; Dynamic stability; Electrochemical analysis; Electrode materials; First principles; Flux density; Ion diffusion; Ion storage; Migration; Nanofibers; Nanowires; Reaction mechanism; Rechargeable batteries; Sodium-ion batteries; Tunnel-type Na0.44MnO2
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2019.04.140

Na0.44MnO2 has drawn great attention as a promising cathode material for sodium-ion batteries (SIBs) owing to its unique tunnel-type structure that allows facile Na+ insertion/extraction. We here report the controllable preparation of Na0.44MnO2 nanowires (NMO NWs) through electrospinning and annealing processes and their SIB cathode application to boost the ionic diffusion dynamics and cyclic stability. The well-shaped NMO NWs with diameters of 50–200 nm effectively favour the easy access to electrolyte, facilitate the electrons/Na+ ions transportation, and retard the active materials fracture/pulverization upon prolonged cycling. Consequently, fascinating electrochemical performance in terms of high-rate capability (120.4 mAh g−1 at 0.1C; 31.7 mAh g−1 at 50C) and unprecedentedly long cycling life (89% capacity retention after 3300 cycles) is achieved. Furthermore, the underlying Na-ion storage mechanism and migration kinetics have been pioneeringly elucidated by a combination study of ex-situ structure/valence analyses and first-principles computations. The pseudocapacitive behaviour of NMO NWs electrode is also identified to benefit the high-rate performance. Finally, a pouch-type sodium-ion full battery assembled by the NMO NWs cathode and hard carbon nanofibers anode delivers an admirable energy density of 165.3 Wh kg−1 and an outstanding capacity retention of 88.57% over 200 cycles, showing great prospects. Well-shaped Na0.44MnO2 nanowires featuring diameters in the range of 50–200 nm enable highly reversible Na+ insertion/extraction through the tunnel-type structure with low ionic diffusion energy barrier and proper pseudocapacitive contribution, demonstrating outstanding high-rate capability and unprecedentedly long cycling life as a cathode for sodium-ion batteries. [Display omitted] •Well-shaped Na0.44MnO2 nanowires were prepared via a controllable and green electrospinning-annealing route.•Na0.44MnO2 nanowires cathode enabled outstanding rate capability and unprecedented cycling stability in Na-ion batteries.•Highly reversible Na+ (de)insertion with low diffusion barrier and proper pseudocapacitive contribution was demonstrated.•A high-energy and long-life pouch-type Na-ion full battery was rationally constructed.