Chen Zhihao, Yu Zuxi, Wang Lifeng, Huang Yingshan, Huang Huijuan, Xia Yuanhua, Zeng Sifan, Xu Rui, Yang Yaxiong, He Shengnan, Pan Hongge, Wu Xiaojun, Rui Xianhong, Yang Hai, Yu Yan
Hefei National Research Center for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Materials Science and Engineering, CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, Anhui 230026, China.
Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621999, China.
ACS Nano. 2023 Sep 12;17(17):16478-16490. doi: 10.1021/acsnano.3c00706. Epub 2023 Aug 17.
Potassium-ion batteries (KIBs) are promising candidates for large-scale energy storage devices due to their high energy density and low cost. However, the large potassium-ion radius leads to its sluggish diffusion kinetics during intercalation into the lattice of the electrode material, resulting in electrode pulverization and poor cycle stability. Herein, vanadium trioxide anodes with different oxygen vacancy concentrations (VO, VO, and VO determined by the neutron diffraction) are developed for KIBs. The VO anode is optimal and exhibits excellent potassium storage performance due to the realization of expanded interlayer spacing and efficient ion/electron transport. X-ray diffraction indicates that VO is a zero-strain anode with a volumetric strain of 0.28% during the charge/discharge process. Density functional theory calculations show that the impacts of oxygen defects are embodied in reducing the band gap, increasing electron transfer ability, and lowering the diffusion energy barriers for potassium ions. As a result, the electrode of nanosized VO embedded in porous reticular carbon (VO@PRC) delivers high reversible capacity (362 mAh g at 0.05 A g), ultralong cycling stability (98.8% capacity retention after 3000 cycles at 2 A g), and superior pouch-type full-cell performance (221 mAh g at 0.05 A g). This work presents an oxygen defect engineering strategy for ultrastable KIBs.
钾离子电池（KIBs）因其高能量密度和低成本，是大规模储能设备的理想候选者。然而，较大的钾离子半径导致其在嵌入电极材料晶格过程中的扩散动力学缓慢，从而造成电极粉化和循环稳定性差。在此，针对钾离子电池开发了具有不同氧空位浓度（通过中子衍射确定的VO、VO和VO）的三氧化钒阳极。VO阳极是最优的，由于实现了层间距扩大和高效的离子/电子传输，表现出优异的钾存储性能。X射线衍射表明，VO是一种零应变阳极，在充放电过程中的体积应变为0.28%。密度泛函理论计算表明，氧缺陷的影响体现在降低带隙、提高电子转移能力以及降低钾离子的扩散能垒上。因此，嵌入多孔网状碳中的纳米级VO电极（VO@PRC）具有高可逆容量（在0.05 A g下为362 mAh g）、超长循环稳定性（在2 A g下3000次循环后容量保持率为98.8%）以及优异的软包型全电池性能（在0.05 A g下为221 mAh g）。这项工作提出了一种用于超稳定钾离子电池的氧缺陷工程策略。
