钴掺杂FeS_(2)的可控制备及储钠特性研究  

Controllable synthesis of Co^(2+)-doped FeS_(2) and their sodium storage performances

作　　者：陈珂君 范利君 CHEN Kejun;FAN Lijun(Xinxiang University,Xinxiang 453000,Henan,China;Hebi Vocational College of Energy and Chemistry,Hebi 458000,Henan,China)

机构地区：[1]新乡学院,河南新乡453000 [2]鹤壁能源化工职业学院,河南鹤壁458000

出　　处：《储能科学与技术》2023年第10期3056-3063,共8页Energy Storage Science and Technology

摘　　要：铁基硫化物作为典型的转化型负极材料,具有理论比容量高、无毒、资源丰富等优势,成为了钠离子电池潜在的负极材料之一。然而,该类材料的电子/离子输运性能较差,导致了储钠动力学特性有待改善,这也限制了其实际应用。基于此,本文以典型铁硫化物FeS_(2)为例,提出阳离子掺杂的策略来调控其晶体结构,以期改善其电化学储钠特性。研究发现,通过在前驱体溶液中引入Co^(2+),实现了钴掺杂FeS_(2)的可控合成。结构和组成表征发现,不同Co^(2+)掺杂量会对FeS_(2)的形貌产生影响,且掺杂后FeS_(2)的(200)晶面间距增大。电化学性能测试表明,掺杂后样品具有更好的倍率性能和循环稳定性。优化样品在电流密度为1 A/g、2 A/g和4 A/g下,分别保持了264.3 mAh/g、224.9 mAh/g和193.4 mAh/g的可逆放电比容量。在1 A/g的电流密度下,循环450次后可保持229.8 mAh/g的放电比容量,容量保持率约为74.6%。储钠动力学分析表明,掺杂后样品显示出更高的Na+扩散效率,同时表现出赝电容占主导的储钠机制。该研究能够为新型钠离子电池负极材料的开发提供理论参考。As typical conversion reaction-type anode materials for sodium-ion batteries(SIBs),iron-base sulfides possess high theoretical capacity,nontoxicity,and nature abundance,making them one of the potential anode materials that can be used in SIBs.However,ironbase sulfides with poor electron/ionic conductivity present a sluggish sodium storage kinetics,which restricts their practical applications.This study utilized iron disulfide(FeS_2) as an example and applies the ion doping strategy to modify the crystal structure and investigate the sample's sodium storage performance.Co^(2+)-doped FeS_(2) is specifically prepared through a feasible and controllable hydrothermal method.The characterization results reveal that the Co^(2+) amount in the precursor solution plays a key role in regulating the sample's microstructure.Moreover,an enlarged interplanar spacing of(200) is observed in FeS_(2).The electrochemical test reveals that the doped materials obtain enhanced rate capabilities and cyclic stability.The optimized sample has revisable specific capacities of 264.3,224.9,and 193.4 m Ah/g at current densities of 1,2,and 4 A/g,respectively.A 229.8 mAh/g reversible discharge capacity is maintained at 1 A/g current density after 400 cycles,corresponding to 74.6% capacity retention.The kinetics analysis illustrates that the doped FeS_(2) presents an improved Na+ diffusion coefficient and a capacitive dominated sodium storage mechanism.This study provides theoretical reference for the fabrication of high-performance anode materials for SIBs.

关 键 词：钠离子电池 掺杂 负极材料 二硫化铁 反应机理 

分 类 号：TM911.1[电气工程—电力电子与电力传动]