摘要
钠离子电池(SIB)由于钠资源的高丰度、广泛可用性和低成本而被认为是EES的候选者。Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)具有结构稳定性强、电压窗口适中、成本低、无绿色污染等优点,被认为是一种极具研究价值的钠离子电池正极材料。Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)的低的电子电导率和铁铝尖晶石不可避免的电化学惰性,在制备过程中,NaFePO_(4)杂质的存在,导致其可逆容量低,循环稳定性差。在此,我们通过一种溶胶凝胶法+球磨法的改进合成方法制备了具有表面N掺杂的二次碳包覆NFCPP正极。表面掺杂、二次碳包覆以及离子掺杂三者协同为NFCPP正极提供了优异的倍率性能(在10 C倍率下82.68 mAh·g^(-1))和出色的循环稳定性,无论是在低倍率(在1.0 C倍率下,100次循环后93.00 mAh·g^(-1),99.00%容量保持率)还是高倍率(在10 C倍率下,1000次循环后77.00 mAh·g^(-1),94.25%容量保持率)。优异电化学性能表明,Cu掺杂减少了NaFePO_(4)杂相的出现,生成了NFPP纯相,同时表面N掺杂的二次碳包覆层和Cu掺杂的结合有利于提高NFPP正极材料的电子导电性,提升了其电化学性能。
Sodium-ion batteries(SIBs)are considered as candidates for EES due to the high abundance,wide availability and low cost of sodium resources.Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is considered as a highly investigated cathode material for SIBs due to its high structural stability,moderate voltage window,low cost,and absence of green pollutants.Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)'s low electronic conductivity and the unavoidable electrochemical inertness of ferroaluminum spinel,and the presence of NaFePO_(4) impurities during its preparation lead to its low reversible capacity and poor cycling stability.Here,we prepared secondary carbon coated NFCPP anode with surface N doping by an improved synthesis method of sol-gel method and ball milling method.The synergistic combination of surface doping,secondary carbon capping,and ionic doping provides NFCPP anodes with excellent multiplicity performance(82.68 mAh·g^(-1) at 10 C multiplication)and outstanding cycling stability,both at low multiplication(93.00 mAh·g^(-1) after 100 cycles at 1.0 C multiplication,99.00%capacity retention)and high multiplication(77.00 mAh·g^(-1) after 1000 cycles,94.25%capacity retention).The excellent electrochemical performance indicates that Cu doping reduces the appearance of NaFePO_(4) heterophase and generates NFPP pure phase,while the combination of surface N-doped secondary carbon cladding and Cu doping facilitates the improvement of the electronic conductivity of the NFPP cathode material and enhances its electrochemical performance.
作者
宋登峰
黎扬
韩影
董静静
王义飞
王新东
Song Dengfeng;Li Yang;Han Ying;Dong Jingjing;Wang Yifei;Wang Xindong(University of Science and Technology Beijing,Beijing 100083 China;Hefei Guoxuan High-Tech Power Energy Co.,Ltd.,Hefei 230000,China)
出处
《广东化工》
2026年第1期24-28,共5页
Guangdong Chemical Industry
基金
低成本长寿命计划(WL-24-08-01)。
