含氧空位的氟掺杂二氧化锰助力稳定锌离子电池

Fluorine⁃doped MnO_(2) with oxygen vacancy for stabilizing Zn⁃ion batteries

将无机盐NH_(4)F加入到Mn O_(2)的前驱体溶液中,通过高效、简单的一步水热法制备了具有氧缺陷的F掺杂α-Mn O_(2)纳米棒(记为F-Mn O_(2))。氧空位和F掺杂对提高F-Mn O_(2)的导电性、促进离子扩散、提高倍率性能起着至关重要的作用。另外,由于F掺杂,形成了F—Mn键,这可以有效地抑制放电产物中Mn^(3+)的Jahn-Teller畸变,从而提高结构的稳定性。得益于这些协同效应,组装的Zn||F-Mn O_(2)全电池在0.5 A·g^(-1)下,首圈放电比容量高达274 m Ah·g^(-1),且具有较长的循环寿命和优异的倍率性能。同时,通过循环伏安(CV)和恒流充放电(GCD)曲线证明了F-Mn O_(2)的储能机制为H^(+)和Zn^(2+)的共嵌入/脱出过程。

Herein,F-doped MnO_(2) with abundant oxygen vacancy(named F-MnO_(2))was synthesized by an efficient and simple one-step hydrothermal method.The introduced oxygen vacancy and pre-intercalated F-doping play a vital role in improving the electrical conductivity of F-MnO_(2) and facilitating ion diffusion,contributing to enhanced rate capability.In addition,the F doping results in the formation of F—Mn bonds,which can effectively inhibit the Jahn-Teller distortion of Mn^(3+)in the discharge product,thus improving the structural stability.Benefiting from these synergic effects,the assembled Zn||F-MnO_(2) full battery exhibited a high capacity of 274 mAh·g^(-1) at 0.5 A·g^(-1),as well as a long cycle life and superior rate performance.Meanwhile,the energy storage mechanism was proved to be a H^(+)and Zn^(2+)co-insertion/extraction process by cyclic voltammetry(CV)and galvanostatic charge-discharge(GCD)tests.