Dimensional Gradient Structure of CoSe2@CNTs–MXene Anode Assisted by Ether for High?Capacity, Stable Sodium Storage

• 作者: Dabin Yu Enze Xu Hanwen Zhu Junjie Quan Lei Chen Li Wang Pengcheng Li Yajing Chang Yang Jiang Zhenjie Sun
• 来源期刊: 纳微快报（英文）
• 年，卷（期）: 2021,（2）
• 页码范围: 377-389
• 页数: 13页
• 语种: 英文

摘要

Recently, abundant resources, low-cost sodium-ion bat-teries are deemed to the new-generation battery in the field of large-scale energy storage. Nevertheless, poor active reaction dynamics, dissolution of intermediates and electrolyte matching problems are significant challenges that need to be solved. Herein, dimensional gra-dient structure of sheet–tube–dots is constructed with CoSe2@CNTs–MXene. Gradient structure is conducive to fast migration of electrons and ions with the association of ether electrolyte. For half-cell, CoSe2@CNTs–MXene exhibits high initial coulomb efficiency (81.7％) and excellent cycling performance (400 mAh g?1 cycling for 200 times in 2 A g?1). Phase transformation pathway from crystalline CoSe2–Na2Se with Co and then amorphous CoSe2 in the discharge/charge process is also explored by in situ X-ray diffraction. Density functional theory study discloses the CoSe2@CNTs–MXene in ether electrolyte system which contributes to stable sodium storage performance owing to the strong adsorption force from hierarchical structure and weak inter-action between electrolyte and electrode interface. For full cell, CoSe2@CNTs–MXene//Na3V2 (PO4)3/C full battery can also afford a competitively reversible capacity of 280 mAh g?1 over 50 cycles. Concisely, profiting from dimensional gradient structure and matched electrolyte of CoSe2@CNTs–MXene hold great application potential for stable sodium storage.