Huang Meng, Wang Xuanpeng, Wang Junjun, Meng Jiashen, Liu Xiong, He Qiu, Geng Lishan, An Qinyou, Yang Jinlong, Mai Liqiang
Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China.
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
Angew Chem Int Ed Engl. 2023 Sep 11;62(37):e202308961. doi: 10.1002/anie.202308961. Epub 2023 Aug 4.
Co-insertion of protons happens widely and enables divalent-ion aqueous batteries to achieve high performances. However, detailed investigations and comprehensive understandings of proton co-insertion are scarce. Herein, we demonstrate that proton co-insertion into tunnel materials is determined jointly by interface derivation and inner diffusion: at the interface, hdrated Mg has poor insertion kinetics, and therefore accumulates and hydrolyzes to produce protons; in the tunnels, co-inserted/lattice H O molecules block the Mg diffusion while facilitate the proton diffusion. When monoclinic vanadium dioxide (VO (B)) anode is tested in Mg(CH COO) aqueous solution, the formation of Mg-rich solid electrolyte interphase on the VO (B) electrode and co-insertion of derived protons are probed; in the tunnels, the diffusion energy barrier of Mg +H O is 2.7 eV, while that of the protons is 0.37 eV. Thus, protons dominate the subsequent insertion and inner diffusion. As a consequence, the VO (B) achieves a high capacity of 257.0 mAh g at 1 A g , a high rate retention of 59.1 % from 1 to 8 A g , and stable cyclability of 3000 times with a capacity retention of 81.5 %. This work provides an in-depth understanding of the proton co-insertion and may promote the development of rechargeable aqueous batteries.
质子的共嵌入现象广泛存在，使得二价离子水系电池能够实现高性能。然而，目前对于质子共嵌入的详细研究和全面理解却较为匮乏。在此，我们证明质子向隧道材料中的共嵌入是由界面衍生和内部扩散共同决定的：在界面处，水合镁的嵌入动力学较差，因此会积累并水解产生质子；在隧道中，共嵌入的/晶格中的水分子会阻碍镁的扩散，同时促进质子的扩散。当在醋酸镁水溶液中测试单斜二氧化钒（VO₂(B)）负极时，我们探究了VO₂(B)电极上富镁固体电解质界面的形成以及衍生质子的共嵌入；在隧道中，Mg + H₂O的扩散能垒为2.7 eV，而质子的扩散能垒为0.37 eV。因此，质子主导了后续的嵌入和内部扩散。结果，VO₂(B)在1 A g⁻¹时实现了257.0 mAh g⁻¹的高容量，在1至8 A g⁻¹之间具有59.1%的高倍率保持率，并且具有3000次的稳定循环性能，容量保持率为81.5%。这项工作为质子共嵌入提供了深入的理解，并可能推动可充电水系电池的发展。
