自掺杂V4 + -V2O5纳米片用于2锂离子插层，具有更高的速率和循环性能,Nano Energy

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自掺杂V4 + -V2O5纳米片用于2锂离子插层，具有更高的速率和循环性能
Nano Energy ( IF 16.8 ) Pub Date : 2016-02-10 13:52:39
Huanqiao Song, Chaofeng Liu, Changkun Zhang, Guozhong Cao

正交晶V ₂ O ₅由于具有高的比容量，易于合成和良好的安全性，被认为是新型锂离子电池（LIB）最有希望的正极材料之一。但是，V ₂ O ₅电极的不良速率和循环性能显着阻碍了它们在高功率和长寿命LIB中的应用。本工作报道了通过在2-乙基咪唑存在下燃烧NH ₄ V ₄ O ₁₀和VO ₂（B）混合物，轻松合成自掺杂的V ⁴⁺ -V ₂ O ₅纳米薄片。所得的V ⁴⁺ -V ₂O ₅表现出优异的速率能力（在100、300、600、1000、2000和4000mAg ^-1时分别具有293、268、234、214、196、196和139mAh g ^-1的可逆容量）和出色的循环性能（95％的容量）在2000mAg ^-1下进行100次放电/充电循环后的保持力）。出色的性能来自于均匀的纳米片状结构，该结构为锂离子插层提供了更大的表面积和反应位点，并且四价钒离子的存在伴随着氧空位，这可能会促进和催化表面的电化学反应，此外与没有检测到V ⁴⁺和氧空位的V ₂ O ₅相比，具有更小的极化和更可逆且更容易的相变，从而提高了本征电导率和Li离子扩散系数。

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Self-doped V4+-V2O5 nanoflake for 2 Li-ion intercalation with enhanced rate and cycling performance

Orthorhombic V₂O₅ has been considered as one of the most promising cathode materials for new lithium ion batteries (LIBs) due to its high specific capacity, easy synthesis and good safety. However, the poor rate and cycling performance of V₂O₅ electrodes significantly impede their applications in high-power and long-life LIBs. The present work reports facile synthesis of self-doped V⁴⁺-V₂O₅ nanoflakes through combusting the NH₄V₄O₁₀ and VO₂ (B) mixture in the presence of 2-ethylimidazole. The resulting V⁴⁺-V₂O₅ exhibited superior rate capability (a reversible capacity of 293, 268, 234, 214, 196 and 139mAh g⁻¹ at 100, 300, 600, 1000, 2000 and 4000mAg⁻¹, respectively) and remarkable cycling performance (95% capacity retention after 100 discharge/charge cycles at 2000mAg⁻¹). The outstanding performance is derived from the uniform nanoflake structure, which offers more surface area and reaction sites for lithium ion intercalation, and the presence of tetravalent vanadium ions accompanied with oxygen vacancies, which might promote and catalyze the electrochemical reactions at the surface, in addition to improve the intrinsic electrical conductivity and Li ion diffusion coefficient, as reflected by the smaller polarization and more reversible and easier phase transitions than those of V₂O₅ without detectable V⁴⁺ and oxygen vacancies.

更新日期：2016-02-11

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