Nanowormlike Li2FeSiO4鈥揅 Composites as Lithium-Ion Battery Cathodes with Superior High-Rate Capability

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• 作者：Xiaozhen Wu ; Xuemin Wang ; Youxiang Zhang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：April 10, 2013
• 年：2013
• 卷：5
• 期：7
• 页码：2510-2516
• 全文大小：499K
• 年卷期：v.5,no.7(April 10, 2013)
• ISSN：1944-8252

文摘

Nanoworm-like Li₂FeSiO₄鈥揅 composites are synthesized using triblock copolymer Pluronic P123 (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), EO₂₀PO₇₀EO₂₀) as the structure directing agent (SDA) and under the effects of ethanol. As a polar nonaqueous cosolvent, ethanol has effects on the self-organization behavior of Pluronic P123 in water, which determines the final morphologies of the Li₂FeSiO₄鈥揅 composites synthesized. Li₂FeSiO₄鈥揅 composite nanoparticles are obtained if no ethanol is added into the system during the synthesis process. When tested as lithium-ion battery cathodes, the Li₂FeSiO₄鈥揅 nanoworms show superior electrochemical performances. At the rate of 1 C (1 C = 166 mA g^鈥?) the discharge capacity of the Li₂FeSiO₄鈥揅 nanoworms can reach 166 mAh g^鈥? in the voltage window of 1.5鈥?.8 V at room temperature. At the rates of 5, 10, and 20 C, the discharge capacities of the Li₂FeSiO₄鈥揅 nanoworms can stabilize at 120, 110, and 90 mAh g^鈥?, respectively, and do not show obvious declines after hundreds of cycles. This performance of the Li₂FeSiO₄鈥揅 nanoworms at high rates is better than that of the Li₂FeSiO₄鈥揅 nanoparticles synthesized and many other Li₂FeSiO₄/C composites reported in the literature. The excellent electrochemical performances of the Li₂FeSiO₄鈥揅 nanoworms are believed to be related to the small sizes of the Li₂FeSiO₄ nanocrystals inside the nanoworms and the carbon that coats and embeds the nanocrystals.

Keywords:

Li₂FeSiO₄鈭扖; nanoworms; cathode materials; lithium ion batteries