A feasibility study on the use of Li(4)V(3)O(8) as a high capacity cathode material for lithium-ion batteries.
A feasibility study on the use of Li(4)V(3)O(8) as a high capacity cathode material for lithium-ion batteries.
复制标题
使用Li(4)V(3)O(8)作为高容量锂离子电池正极材料的可行性研究。
作者：
S. Ng;N. Tran;K. Bramnik;H. Hibst;P. Novák
采用喷雾干燥法制备球形Li(1.1)V(3)O(8)前驱体材料，用Li(2)S化学锂化法制备Li(4)V(3)O(8)材料。通过扫描电子显微镜（SEM）和x射线衍射（XRD）对过锂化钒酸盐进行了物理表征，并在半电池（相对于锂金属）和全电池（相对于石墨）体系中使用恒流充放电和循环伏安法进行了电化学测量。Li(4)V(3)O(8)材料在空气中稳定长达5小时，在空气中储存的样品几乎没有容量下降。然而，长时间暴露在空气中会严重改变Li(4)V(3)O(8)材料的组成，导致Li(1.1)V(3)O(8)和Li(2)CO(3)。这些过锂化钒酸盐的电化学性能对阴极中导电添加剂（炭黑）含量非常敏感。当加入足够的炭黑时，Li(4)V(3)O(8)阴极表现出良好的循环性能和优异的倍率能力，与Li(1.1)V(3)O(8)前驱体材料相匹配，即在2800 mA g（-1）下保持205 mAh g（-1）的平均充电容量（8C倍率；1C倍率意味着电池在一小时内充满或放电），相对于锂金属在2.0-4.0 V的电位范围内循环。当应用于非优化的全电池系统（相对于石墨）时，Li(4)V(3)O(8)阴极显示出良好的循环性能，当在1.6-4.0 V电压范围内，在117 mA g(-1) （C/3比率）的特定电流下循环50次时，其充电容量（Li（+）萃取）保持在130 mAh g（-1）以上。
Li(4)V(3)O(8) materials have been prepared by chemical lithiation by Li(2)S of spherical Li(1.1)V(3)O(8) precursor materials obtained by a spray-drying technique. The over-lithiated vanadates were characterised physically by using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and electrochemically using galvanostatic charge-discharge and cyclic voltammetry measurements in both the half-cell (vs. Li metal) and full-cell (vs. graphite) systems. The Li(4)V(3)O(8) materials are stable in air for up to 5 h, with almost no capacity drop for the samples stored under air. However, prolonged exposure to air will severely change the composition of the Li(4)V(3)O(8) materials, resulting in both Li(1.1)V(3)O(8) and Li(2)CO(3). The electrochemical performance of these over-lithiated vanadates was found to be very sensitive to the conductive additive (carbon black) content in the cathode. When sufficient carbon black is added, the Li(4)V(3)O(8) cathode exhibits good cycling behaviour and excellent rate capabilities, matching those of the Li(1.1)V(3)O(8) precursor material, that is, retaining an average charge capacity of 205 mAh g(-1) at 2800 mA g(-1) (8C rate; 1C rate means full charge or discharge of a battery in one hour), when cycled in the potential range of 2.0-4.0 V versus Li metal. When applied in a non-optimised full cell system (vs. graphite), the Li(4)V(3)O(8) cathode showed promising cycling behaviour, retaining a charge capacity (Li(+) extraction) above 130 mAh g(-1) beyond 50 cycles, when cycled in the voltage range of 1.6-4.0 V, at a specific current of 117 mA g(-1) (C/3 rate).