Heterogeneous MoSe2/Nitrogen‐Doped‐Carbon Nanoarrays: Engineering Atomic Interface for Potassium‐Ion Storage

• Published in: Advanced functional materials 2022-02, Vol.32 (8), p.n/a
• Main Authors: Xu, Da, Chen, Ling, Su, Xiaozhi, Jiang, Hongliang, Lian, Cheng, Liu, Honglai, Chen, Long, Hu, Yanjie, Jiang, Hao, Li, Chunzhong
• Format: Article
• Language: English
• Subjects: Anodes; Carbon; Diffusion rate; electrochemical reversibility; Electrode materials; geometric structures; heterogenous interfaces; Interlayers; Ion diffusion; Ion storage; K‐ion batteries; Lithium-ion batteries; Materials science; Molybdenum compounds; MoSe 2; Nitrogen; Regeneration
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202110223

Owing to the lower price and higher safety, developing high‐performance K‐ion batteries (KIBs) is of great significance as an alternative to Li‐ion batteries. High‐energy‐density MoSe2 has been identified as a promising anode material for KIBs; however, its electrochemical reversibility remains a big challenge. Herein, heterogenous MoSe2/N‐doped carbon nanoarrays demonstrate a brilliant performance as KIBs anode materials. The as‐formed hetero‐interface weakens the KSe bond of discharged products (K2Se), the length of KSe bond is stretched by 3.9% with an enlargement of 19.2% in angle compared with pure K2Se, greatly promoting the regeneration of MoSe bond during charge. Moreover, the atomically inter‐overlapping feature leads to an expanded MoSe2 interlayer distance of 1.20 nm that enables a much faster K‐ion diffusion. Consequently, this nanoarray delivers an unprecedented K‐ion storage performance, that is, a capacity of 402 mAh g−1 at 0.2 A g−1 over 200 cycles, and a long cycle life over 1000 cycles at 1.0 A g−1 with 307 mAh g−1 capacity retention. The heterogenous MoSe2/N‐doped carbon nanoarrays demonstrate a brilliant performance as K‐ion batteries anode materials with greatly enhanced reversibility. The as‐formed heterointerface greatly weakens the KSe bond of the discharge product (K2Se) by optimizing its geometric structure, leading to the easy regeneration of the MoSe bond. The K‐ion storage mechanism and structure‐performance relationship are further clarified during de‐/potassiation.