Pillar-beam structures prevent layered cathode materials from destructive phase transitions

• Published in: Nature communications Vol. 12; no. 1; pp. 13 - 11
• Main Authors: Wang, Yuesheng, Feng, Zimin, Cui, Peixin, Zhu, Wen, Gong, Yue, Girard, Marc-André, Lajoie, Gilles, Trottier, Julie, Zhang, Qinghua, Gu, Lin, Wang, Yan, Zuo, Wenhua, Yang, Yong, Goodenough, John B., Zaghib, Karim
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04.01.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 147/137; 639/301/299/891; 639/4077/4079/891; 639/638/161/891; Anions; Cathodes; Commercialization; Electrode materials; Energy storage; Flux density; Gas evolution; Humanities and Social Sciences; Ions; multidisciplinary; Phase transitions; Potassium; Rechargeable batteries; Science; Science (multidisciplinary); Sodium; Sodium-ion batteries; Specific capacity; Transition metals
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-20169-1

Energy storage with high energy density and low cost has been the subject of a decades-long pursuit. Sodium-ion batteries are well expected because they utilize abundant resources. However, the lack of competent cathodes with both large capacities and long cycle lives prevents the commercialization of sodium-ion batteries. Conventional cathodes with hexagonal-P2-type structures suffer from structural degradations when the sodium content falls below 33%, or when the integral anions participate in gas evolution reactions. Here, we show a “pillar-beam” structure for sodium-ion battery cathodes where a few inert potassium ions uphold the layer-structured framework, while the working sodium ions could diffuse freely. The thus-created unorthodox orthogonal-P2 K 0.4 [Ni 0.2 Mn 0.8 ]O 2 cathode delivers a capacity of 194 mAh/g at 0.1 C, a rate capacity of 84% at 1 C, and an 86% capacity retention after 500 cycles at 1 C. The addition of the potassium ions boosts simultaneously the energy density and the cycle life. The specific capacity of P2-type sodium-ion battery cathode is limited because full extraction of Na ions leads to structural degradation. Here authors report pillar-beam structured material to overcome this issue by using K pillar ions to uphold the transition metal layers upon extraction of Na ions.