摘要
以离子液体为碳源和氮源、次亚磷酸钠为磷源、乙酸镍为镍源,一步法制备了磷化镍/氮磷共掺杂碳(Ni_(2)P/NPC)复合材料。SEM、TEM等检测结果表明Ni_(2)P纳米颗粒在N、P共掺杂碳骨架上均匀分布。将所制备Ni_(2)P/NPC作为锂离子电池负极材料时,Ni_(2)P/NPC电极在0.1、0.5、1、3和5 A·g^(-1)电流密度下的放电比容量分别为377.7、294.1、265.4、211.7和187.5 mAh·g^(-1)。当电流密度重新回到0.1 A·g^(-1),放电比容量为368.1 mAh·g^(-1)。电极结构在大倍率下可以保持稳定,表现出优异的倍率性能。在0.5 A·g^(-1)的电流密度下经200次循环后放电比容量维持在301.8 mAh·g^(-1),容量保持率为80.7%,CV曲线证实Ni_(2)P/NPC在储锂过程中是由扩散过程和电容行为共同控制。
In recent years,the nickel-based phosphide has drawn great attention because of its low intercalation/deintercalation platform and lower polarization compared to sulfides and oxides as anodes for next-generation high-energy lithium-ion batteries.The Ni_(2)P anode can deliver high theoretical specific capacity of 542 mAh·g^(-1),but it subject to a conversion reaction mechanism,which make them unsuitable for commercial applications.The agglomeration of Ni_(2)P nanoparticles during material fabrication and the structural deterioration of electrode associated with large volume change during charge-discharge process lead to poor cycle stability and low utilization of active materials.Meanwhile,the low intrinsic conductivity of Ni_(2)P is also sluggish electrochemical reaction kinetics.Herein,we design a facile and viable approach to synthesize Ni_(2)P/NPC composites with a stable structure to address these issues.This new approach entails synthesis of Ni_(2)P/NPC by a N and P co-doped carbon framework with ionic liquids assistance during synthesis.This stable composite structure can serve as anode material of lithium ion batteries with good electrochemical performance.The Ni_(2)P/NPC composites were prepared by one-step method using ionic liquids as carbon and nitrogen sources,while sodium hypophosphite and nickel acetate as phosphorus and nickel sources,respectively.The results of SEM and TEM show that Ni_(2)P nanoparticles were uniformly distributed on the N and P co-doped carbon framework.When the Ni_(2)P/NPC composite was used as an anode material of lithium ion batteries,the discharge specific capacities were 377.7,294.1,265.4,211.7 and 187.5 mAh·g^(-1) at 0.1,0.5,1,3 and 5 A·g^(-1),respectively.When the current density returned to 0.1 A·g^(-1),the discharge specific capacity reached 368.1 mAh·g^(-1).The Ni_(2)P/NPC structure could be kept stable at high rate,showing excellent rate performance.The fabricated Ni_(2)P/NPC anode delivered the discharge specific capacity of 301.8 mAh·g^(-1) with the capacity re
作者
胡健
蒙延双
胡倩茹
Jian Hu;Yan-Shuang Meng;Qian-Ru Hu(School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730000,Gansu China)
出处
《电化学》
CAS
CSCD
北大核心
2021年第5期540-548,共9页
Journal of Electrochemistry
基金
国家自然科学基金项目(No.51404124)
省部共建有色金属先进加工与再利用国家重点实验室开放基金(No.SKLAB02019015)资助。
关键词
磷化镍
氮磷共掺杂碳
储锂
nickel phosphide
nitrogen and phosphorous co-doped carbon
lithium storage
