微波辅助合成非晶态钴掺杂磷酸镍电化学储能电极材料

Microwave Assisted Synthesis of Amorphous Cobalt Doped Nickel Phosphate as Electrode Materials for Electrochemical Energy Storage

杂原子掺杂被认为是调节电极材料电子结构以提高电容性能和循环稳定性的有效途径,采用微波辅助的方法,通过后续热处理,成功获得了具有3D花状结构的钴掺杂磷酸镍.随后,将其组装成了具有良好电化学性能的非对称超级电容器(ASC).得益于钴和镍在煅烧过程中的协同作用和结构效应,团聚的纳米颗粒逐渐转变为粒径均匀的微观花状结构.作为电极材料在电流密度为1 A·g^(−1)时,由于Ni和Co之间的协同作用增加了OH−吸附能,所制备材料的比容量达到了1214 F·g^(−1).电化学测试进一步表明,在1 A·g^(−1)下循环3000次后,电极的电容保持率达到了83.9%.以钴掺杂磷酸镍为正极、还原氧化石墨烯为负极组装的超电器件在功率密度为750 W·kg^(−1)的情况下,能量密度为26.25 Wh·kg^(−1),循环稳定性良好.这也表明所设计钴掺杂磷酸镍3D花状微结构在混合超级电容器中具有一定的应用前景.

Heteroatom doping has been regarded as an effective route to tune the electronic structure of electrode materials to achieve enhanced capacitive performance and cycling stability.Herein,cobalt doped nickel phosphate equipped with 3D flower-like microstructure was successfully obtained by a facile microwave assisted method with follow-up thermal treatment.Subsequently,it was assembled into an asymmetric supercapacitor(ASC)with good electrochemical performance.Interestingly,benefitting from the synergistic and structural effects of cobalt and nickel during calcination,the agglomerated nanoparticles gradually transform into microscopic flower-like structure with uniform size.Then,a battery-type electrode based on the cobalt doped nickel phosphate was fabricated and exhibited an excellent specific capacity of 1214 F·g^(−1)at the current density of 1 A·g^(−1)due to the increased OH−adsorption energy given by the synergistic effect between Ni and Co.It’s noted that an outstanding capacitance retention was delivered(83.9%maintained after 3000 cycles at 1 A·g^(−1)).Furthermore,ASC assembled with the cobalt doped nickel phosphate as the positive electrode and rGO as the negative electrode demonstrates a high energy density of 26.25 Wh·kg^(−1)at a power density of 750 W·kg^(−1)and outstanding cycling stability.Our results suggest that the design of cobalt doped nickel phosphate 3D flower-like microstructure owns great prospect for application to hybrid supercapacitor.