Poly(vinylpylrrolidone) as Surfactant in the Sol-Gel Preparation of Lithium Iron Phospate/Carbon Cathodes for Lithium-Ion Batteries

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• 作者：Dr. Changling Fan ; Qiyuan Li ; Dr. Shilin Chen ; Jiwei Fan ; Zheng Wen ; Taotao Zeng ; Dr. Xiang Zhang and Prof. Shaochang Han
• 刊名：Energy Technology
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：4
• 期：8
• 页码：973-979
• 全文大小：1399K
• ISSN：2194-4296

文摘

Lithium iron phosphate/carbon (LiFePO₄/C) is synthesized by a modified sol–gel method, in which the nonionic surfactant poly(vinylpyrrolidone) (PVP) is used. PVP plays a dual roles in the preparation of LiFePO₄/C: it is used as surfactant to prevent the colloid particles and carbon source from aggregating, and is a carbon source. The carbon contents and conductivities of LiFePO₄/C increase with increasing of PVP. When the ratio of PVP to LiFePO₄ reaches 1 ‰, the conductivity of LiFePO₄/C reaches its optimal value of 2.67×10⁻² S cm⁻¹ and its discharge capacity at 1 C is 131.0 mAh g⁻¹. This is because the use of PVP leads particles that are small and have a homogeneous size distribution, which is due to dispersion by PVP. Titanium (Ti⁴⁺)-doped samples, obtained from a sol–gel method, possess even better performances. The discharge capacities of this sample is 111.1 mAh g⁻¹at 5 C and 87.3 mAh g⁻¹ at 8 C. The gap in potential between the oxidative and reductive peaks is as low as 0.2053 V, which shows its reversibility is excellent.