Structural engineering of hydrated vanadium oxide cathode by K+ incorporation for high-capacity and long-cycling aqueous zinc ion batteries
Structural engineering of hydrated vanadium oxide cathode by K+ incorporation for high-capacity and long-cycling aqueous zinc ion batteries
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DOI：
10.1016/j.ensm.2020.03.024
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发表时间：
2020-08-01
影响因子：
20.4
通讯作者：
Cao, Guozhong
中科院分区：
文献类型：
--
作者：
Tian, Meng;Liu, Chaofeng;Cao, Guozhong
钒氧化物具有低成本、高容量的优点，是水基锌离子电池正极材料的理想候选材料，但长期循环的要求要求其结构的稳定性越来越高。本研究报道了一种结构工程方法，将K+引入水合五氧化二钒(V2O5中心点NH(2)O，VOH)中，得到独特的水合钒酸盐(KV12O30-y中心点NH(2)O，KVOH)。与以前报道的工作不同，K+的引入导致了新的KVOH相，具有更快的离子扩散动力学和更好的长期循环稳定性。这项工作建立了对K+在KVOH中的作用的理解，它超越了传统的层间距调节剂类别，反映在即使在高速率下也能保持有效的锌离子插入/提取的结构灵活性，通过V4+/V5+的电子希望改善材料的导电性，并作为稳定剂以较小的电压滞后和更高的可逆性来适应结构的收缩/膨胀。KVOH在0.05Ag(-1)时的容量为436mAg(-1)，在10Ag(-1)时的容量为227mAg(-1)，优于VOH和已报道的大多数引入钒酸盐的单价和多价金属离子。KVOH表现出优异的循环稳定性，在5Ag(-1)、高能量密度(308Wh kg(-1))和功率密度(7502W kg(-1))下循环3000次容量保持92%，并提高了能量效率。这些特性建议将KVOH阴极用于高性能水基ZIB。
Vanadium oxides are promising candidates for cathode materials in aqueous zinc-ion batteries (ZIBs) with low cost and high capacity yet requirements for long cycling necessitate the development of increasingly stable structure. This study reports a structural engineering method by incorporating K+ into hydrated vanadium pentoxide (V2O5 center dot nH(2)O, VOH) to achieve unique hydrated vanadate (KV12O30-y center dot nH(2)O, KVOH). In contrast to previously reported works, K+ introduction leads to a new phase of KVOH with faster ion diffusion kinetics and better long-term cycling stability. This work establishes an understanding of the role of K+ incorporation in KVOH which goes beyond its conventional categorization as an agent for interlayer spacing adjustment, reflecting in maintaining structure flexibility for effective Zn2+ insertion/extraction even at high rates, improving materials conductivity by the electron hoping of V4+/V5+ and acting as a stabilizer to accommodate structural contraction/ expansion with smaller voltage hysteresis and higher reversibility. KVOH displays a remarkable capacity of 436 mAh g(-1) at 0.05 A g(-1), maintains 227 mAh g(-1) at 10 A g(-1), which is better than VOH and the majority of reported monovalent and multivalent metal ions introduced in vanadates. KVOH exhibits excellent cycling stability with 92% capacity retention over 3000 cycles at 5 A g(-1), high energy density (308 Wh kg(-1)) and power density (7502 W kg(-1)), as well as improved energy efficiency. These characteristics recommend KVOH cathodes for use in high-performance aqueous ZIBs.