High-Performance Olivine NaFePO4 Microsphere Cathode Synthesized by Aqueous Electrochemical Displacement Method for Sodium Ion Batteries

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• 作者：Yongjin Fang ; Qi Liu ; Lifen Xiao ; Xinping Ai ; Hanxi Yang ; Yuliang Cao
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：August 19, 2015
• 年：2015
• 卷：7
• 期：32
• 页码：17977-17984
• 全文大小：519K
• ISSN：1944-8252

文摘

Olivine NaFePO₄/C microsphere cathode is prepared by a facile aqueous electrochemical displacement method from LiFePO₄/C precursor. The NaFePO₄/C cathode shows a high discharge capacity of 111 mAh g^鈥?, excellent cycling stability with 90% capacity retention over 240 cycles at 0.1 C, and high rate capacity (46 mAh g^鈥? at 2 C). The excellent electrochemical performance demonstrates that the aqueous electrochemical displacement method is an effective and promising way to prepare NaFePO₄/C material for Na-based energy storage applications. Moreover, the Na_2/3FePO₄ intermediate is observed for the first time during the Na intercalation process through conventional electrochemical techniques, corroborating an identical two-step phase transition reaction both upon Na intercalation and deintercalation processes. The clarification of the electrochemical reaction mechanism of olivine NaFePO₄ could inspire more attention on the investigation of this material for Na ion batteries.