材料科学
阳极
锗
锂(药物)
结晶度
柠檬酸
煅烧
无机化学
化学工程
电化学
氧化物
冶金
化学
电极
硅
催化作用
复合材料
物理化学
医学
生物化学
有机化学
工程类
内分泌学
作者
Yang Gao,Yakun Tang,L. X. Liu,Xiaohui Li,Mao Qian,Wenjie Ma
出处
期刊:Small
[Wiley]
日期:2023-08-11
标识
DOI:10.1002/smll.202304593
摘要
To obtain anode materials with high capacity/energy density for lithium-ion batteries, a polyanionic compound Li2 FeGeO4 is prepared, which combines the conversion-type Fe-based oxide and the alloy-type Ge-based oxide at the atomic scale. The influence of citric acid in the sol-gel process on the structure and performance of the calcined products (LFG0, LFG1, and LFG2) is investigated. The results demonstrate that citric acid does not affect the phase of Li2 FeGeO4 . However, with the increase of citric acid, the crystallinity and grain size of the final product are reduced and its dispersion becomes better. Among the as-prepared samples, LFG1 exhibits moderate particle size and more uniform dispersion, providing a high discharge capacity of 669.7 mAh g-1 at 0.5 A g-1 after 200 cycles. Based on the ex situ XPS and operando XRD tests, it is found that the electrochemical reaction process of LFG1 is controlled by both the conversion of iron/germanium and the alloying of germanium. In addition, it is verified that the reaction mechanism of LFG1 for aqueous lithium-ion capacitors is also controlled by iron and germanium elements. Importantly, Li2 FeGeO4 is first proved to be a novel anode for lithium-ion batteries and lithium-ion capacitors.
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