铁基普鲁士蓝正极材料的宏量制备及电化学储钠性能

以柠檬酸钠作为配位剂,采用共沉淀法,在室温下制备了铁基普鲁士蓝材料(FePB)。当使用20 L容积的反应釜,并将前驱体亚铁氰化钠(Na_4Fe(CN)_6])的浓度提高至0.5 mol·L~(-1)时,制备一次可实现高达500 g的产量。电化学测试显示,所得FePB材料具有较高的容量、优异的倍率性能和良好的循环寿命。在0.1C时,该材料首次放电比容量可达到117 mAh·g~(-1),在10C的大电流密度下,比容量仍可保持在92 mAh·g~(-1)。在1C电流密度下,经过500次循环,比容量仍保持在87 mAh·g~(-1),容量保持率达到89%。以商业硬碳为负极,以FePB为正极,制作了软包钠离子全电池。该软包电池在50 mA的电流下,经过400次循环可实现75%的容量保持率。FePB材料优异的电化学性能与其较高的钠含量、低的缺陷、多边界的微观结构以及普鲁士蓝类材料独特的开放框架结构有关。

Scalable Preparation and Electrochemical Sodium-Storage Performance of Fe-Based Prussian Blue Cathode Material

Fe-based Prussian blue material (FePB) was synthesized by coprecipitation method at room temperature using sodium citrate as chelating agent. A high yield of 500 g per preparation can be obtained by using a 20 L reactor and a Na₄Fe(CN)₆ precursor with a concentration up to 0.5 mol·L^-1. The results of electrochemical measurements indicate that the obtained FePB showed a high capacity, excellent rate capability and long cycle life. At 0.1C, the first discharge capacity of FePB reached 117 mAh·g^-1. At a current density as high as 10C, the FePB can still yield a discharge capacity of 92 mAh·g^-1. After 500 cycles at 1C, a specific capacity of 87 mAh·g^-1 still maintained with a retention of 89%. Pouch-type Na-ion full battery was fabricated using commercial hard carbon as anode and FePB as cathode, which exhibited a capacity retention of 75% after 400 cycles at 50 mA. The excellent electrochemical performance of the FePB is attributed to its high sodium content, low defect, border-rich microstructure and the unique open framework structure of the Prussian blue analogues.