苯胺-邻硝基苯胺共聚物——高比容量锂二次电池新型正极材料

Poly(Aniline/o-Nitroaniline):A High Capacity Cathode Material for Lithium Ion Batteries

聚苯胺作为锂离子电池典型的有机正极材料,合成简单、资源丰富,但其电化学比容量与循环寿命始终难以满足实用要求.作者采用化学氧化聚合法合成了苯胺-邻硝基苯胺共聚物(Poly(Aniline/o-Nitroanil-ine,P(AN-oNA)),通过在聚苯胺主链引入强拉电子基团——硝基苯胺,增大共聚物的电子共轭体系,改善共聚物链段的稳定性,利用硝基苯胺基团的电化学可逆性提高共聚物的电化学活性.结果表明,P(AN-oNA)的初始充放电比容量高达186 mAh·g-1,比聚苯胺提高近37%,60周循环仍能维持168 mAh·g-1.此外,P(AN-oNA)电极的充放电电位平阶十分接近,电极的极化明显降低,电子转移反应速率加快.这种新型共聚物结构与性能对于发展有机正极材料具有重要的参考意义.

Polyaniline can be used as a high capacity cathode material due to the advantages of material abun-dance and synthetic simplicity. However, its practical application in battery has been hindered by poor electro-chemical utilization and cycling instability. To solve these problems, we synthesized the poly （ aniline/o-Nitro-aniline） （P（AN-oNA） ） by introducing the electron-drawing group-nitroaniline onto the polyaniline chains, so as to enhance electrochemical utilization and stability of the polyaniline derivative. The as-prepared Li/P（ AN- oNA） copolymer shows a greatly enhanced discharge capacities of 186 mAh·g^-1 at initial cycles, about 37 % higher than its parent PAN, and remains 168 mAh·g^-1 after 60th cycle. Also, the Li/P（AN-oNA） copolymer exhibits ,Jery similar charge and discharge profiles, demonstrating a significantly decreased polarization. This structural modification of PAN and the resulting improved performances of the Li/P （AN-oNA） copolymer suggest an effective way to develop high capacity organic cathode materials for Li-ion batteries.