High Cycling Stability of the LiNi0.8Co0.1Mn0.1O2 Cathode via Surface Modification with Polyimide/Multi-Walled Carbon Nanotubes Composite Coating

The Ni-rich LiNi0.8Co0.10Mn0.1O2 (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(-1) between 2.8 and 4.3 V at 0.1 C @ 25 degrees C, which is slightly lower than that of NCM811 (201.1 mAh g(-1)). 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.

Automated summary

The modified Ni-rich LiNi0.8Co0.10Mn0.1O2 (NCM811) cathode as PI3-NCM811 shows significantly improved cycling stability and delayed secondary crystal cracking. The PI3-NCM811 cathode exhibits better capacity retention after 500 cycles compared to NCM811.