磷掺杂钴酸铁电极材料用于非对称超级电容器

Phospho-doped FeCo_(2)O_(4)Electrode Material for Asymmetric Supercapacitors

采用简单的水热法和低温磷化法在柔性碳布上原位生长磷掺杂的钴酸铁纳米线(P-FeCo_(2)O_(4-x))电极材料,研究了不同磷源加入量对P-Fe Co_(2)O_(4-x)的形貌和性能的影响。结果表明:当加入的磷源量为400mg时,所制备的P-FeCo_(2)O_(4-x)-2电极材料具有优异的电化学性能,在5m A/cm^(2)的电流密度下表现出3643m F/cm^(2)的比电容,在20m A/cm^(2)的电流下充放电循环5000次后容量保持率为85.9%。性能提升的主要原因得益于磷掺杂到尖晶石结构中,取代了部分氧原子的位置并形成氧空位,提高缺陷程度的同时,改善了电子结构,提高了电导率。进一步组装成柔性非对称超级电容器,其正极为P-FeCo_(2)O_(4-x)-2材料,负极为活性炭(AC)。该电容器在功率密度达到747.4W/kg的情况下,展现出高达40.9Wh/kg的出色能量密度。此外,经过2000次充放电循环测试,即使在5A/g的电流密度下,其容量保持率依然稳定在82.1%。

Phosphorus-doped FeCo_(2)O_(4)nanowire(P-FeCo_(2)O_(4-x))electrode materials were grown in situ on flexible carbon cloth using simple hydrothermal and low-temperature phosphorylation methods,and the effects of various phosphorus source additions on the morphology and properties of P-FeCo_(2)O_(4-x)were investigated.The results showed that the prepared P-FeCo_(2)O_(4-x)-2 electrode materials had uniform and rough morphology and excellent electrochemical properties at a current density of 5 mA/cm^(2)with a specific capacitance of 3643 mF/cm^(2)and a capacity retention rate of 85.9%after 5000 charge/discharge cycles at current of 20 mA/cm^(2).The performance enhancement is mainly attributed to the doping of phosphorus into the spinel structure,which replaces some of the oxygen atoms and forms oxygen vacancies,increasing the degree of defects,while improving the electronic structure and increasing the conductivity.Being assembled into a flexible asymmetric supercapacitor,the positive pole is P-FeCo_(2)O_(4-x)-2 material,and the negative pole is activated carbon(AC).The capacitor exhibits an excellent energy density of 40.9 Wh/kg at a power density of 747.4 W/kg.In addition,after 2000 charge-discharge cycles,the capacity retention rate remains stable at 82.1%,even at a current density of 5 A/g.