Zha Guojun, Ouyang Chuying, Yin Shungao, Yao Kaiqing, Agarwal Seema, Hu Naigen, Hou Haoqing
College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, China.
School of New Energy Science and Engineering, Xinyu University, Xinyu, China.
Small. 2021 Nov;17(47):e2102981. doi: 10.1002/smll.202102981. Epub 2021 Sep 29.
The Ni-rich LiNi Co Mn O (NCM811) cathode coated by combining with multi-walled carbon nanotubes (MWCNTs) and polyimide (PI) produces a PI3-NCM811 cathode, which markedly improves cycling stability and suppresses secondary crystal cracking. The initial discharge capacity of the PI3-NCM811 cathode is 199.6 mAh g between 2.8 and 4.3 V at 0.1 C @ 25 °C, which is slightly lower than that of NCM811 (201.1 mAh g ). The PI3-NCM811 and NCM811 cathodes keep 90.6% and 64.8% of their initial discharge capacity at 1 C between 2.8 and 4.3 V after 500 cycles, respectively. Furthermore, the difference (21.1%) in capacity retention rate between PI3-NCM811 and NCM811 under the condition of 2.8-4.5 V became smaller compared with the difference (25.8%) under the condition of 2.8-4.3 V. This better cyclic stability is mainly attributed to the toughness and elasticity of PI, which inhibits the secondary cracking, maintains the structural integrity of the cathode particles, and protects the particles from electrolyte damage during long-term cycling.
通过与多壁碳纳米管（MWCNTs）和聚酰亚胺（PI）结合包覆的富镍LiNiCoMnO（NCM811）正极制备出PI3-NCM811正极，其显著提高了循环稳定性并抑制了二次晶体开裂。PI3-NCM811正极在25℃下0.1C时2.8至4.3V之间的初始放电容量为199.6mAh/g，略低于NCM811（201.1mAh/g）。PI3-NCM811和NCM811正极在1C下2.8至4.3V之间循环500次后，分别保持其初始放电容量的90.6%和64.8%。此外，与2.8至4.3V条件下的差异（25.8%）相比，PI3-NCM811和NCM811在2.8至4.5V条件下的容量保持率差异（21.1%）变小。这种更好的循环稳定性主要归因于PI的韧性和弹性，其抑制了二次开裂，维持了正极颗粒的结构完整性，并在长期循环过程中保护颗粒免受电解液损伤。
