High-Temperature-Annealed Multi-Walled Carbon Nanotubes as High-Performance Conductive Agents for LiNi0.5Co0.2Mn0.3O2 Lithium-Ion Batteries

Abstract

In this work, the high yield of MWNTs was prepared by chemical vapor deposition (CVD) method, followed by annealing at 2000–2800 °C, and the effects of high annealing temperature on metal impurities and defects in multi-walled carbon nanotubes (MWNTs) was explored. Furthermore, the annealed MWNTs were dispersed using a sand mill to make a conductive slurry, and finally the cathode LiNi0.5Co0.2Mn0.3O2 was added to the assembled batteries, and the application of MWNTs (slurry) as conductive agents in LiNi0.5Co0.2Mn0.3O2 (NCM) cathode materials by sand-mill dispersion on the performance of lithium-ion batteries was investigated. The results indicate that high temperature annealing can effectively remove the residual metal impurities from MWNTs and the defects in MWNTs gradually decreases as the temperature rises. In addition, 2 wt% of MWNTs (slurry) in LiNi0.5Co0.2Mn0.3O2 is sufficient to form an electronically conductive network; as a result, the electronic conductivity and the high rates performance of the LiNi0.5Co0.2Mn0.3O2 batteries were greatly improved. The LiNi0.5Co0.2Mn0.3O2 battery with MWNTs slurries annealed at 2200 ℃ as a conductive additive displays the highest initial discharge capacity of 173.16 mAh·g−1 at 0.1 C. In addition, after 100 cycles, a capacity retention of 95.8% at 0.5 C and a discharge capacity of 121.75 mAh·g−1 at 5 C were observed. The multi-walled carbon nanotubes used as conductive agents in LiNi0.5Co0.2Mn0.3O2 (NCM) cathode materials show excellent battery behaviors, which would provide a new insight for the development of high-performance novel conductive agents in lithium-ion batteries.

Promoting Effect of Ball Milling on the Functionalization and Catalytic Performance of Carbon Nanotubes in Glycerol Etherification

“…This finding also aligns with the increased ash in this sample (see Figure 1). Residues of the CCVD catalyst trapped in the CNT structure were also observed in TEM images presented elsewhere [40,41].…”

“…This finding also aligns with the increased ash in this sample (see Figure 1). Residues of the CCVD catalyst trapped in the CNT structure were also observed in TEM images presented elsewhere [40,41]. Interestingly, ball milling increased the S BET of NC7000, most likely due to agglomerates' fragmentation, shortening of the tubes, and caps opening during the mechanical treatment [19,39].…”

Effect of S-doped carbon nanotubes as a positive conductive agent in lithium-ion batteries

“…Due to the requirements for stability and resistance to acid and alkaline corrosion, conductive additives in lithium-ion batteries are mostly carbon-based materials [8][9][10][11] , including conductive carbon black, conductive graphite, carbon bers, graphene, and carbon nanotubes. In addition to their excellent electrical conductivity, carbon nanotubes have a ber-like structure that provides good exibility and mechanical stability [12][13][14] , It is conducive to improving the processability of the battery plate and the cycle life of the battery. Therefore, they are favored by researchers and manufacturers.…”

“…Conductive additives can increase the conductive contact between active materials, improve the electronic conductivity, generate micro-current between active materials and collector surfaces, reduce electrode contact resistance, accelerate electron mobility [5][6][7] .Therefore, it is often necessary to add additional conductive materials to improve battery performance.Due to the requirements for stability and resistance to acid and alkaline corrosion, conductive additives in lithium-ion batteries are mostly carbon-based materials [8][9][10][11] , including conductive carbon black, conductive graphite, carbon bers, graphene, and carbon nanotubes. In addition to their excellent electrical conductivity, carbon nanotubes have a ber-like structure that provides good exibility and mechanical stability [12][13][14] , It is conducive to improving the processability of the battery plate and the cycle life of the battery. Therefore, they are favored by researchers and manufacturers.Common preparation methods for carbon nanotubes include arc discharge, laser evaporation and chemical vapor deposition [15][16][17] .…”

Effect of S-doped carbon nanotubes as a positive conductive agent in lithium-ion batteries

“…Conductive additives can increase the conductive contact between active materials, improve the electronic conductivity, generate micro-current between active materials and collector surfaces, reduce electrode contact resistance, accelerate electron mobility [5][6][7] .Therefore, it is often necessary to add additional conductive materials to improve battery performance.Due to the requirements for stability and resistance to acid and alkaline corrosion, conductive additives in lithium-ion batteries are mostly carbon-based materials [8][9][10][11] , including conductive carbon black, conductive graphite, carbon bers, graphene, and carbon nanotubes. In addition to their excellent electrical conductivity, carbon nanotubes have a ber-like structure that provides good exibility and mechanical stability [12][13][14] , It is conducive to improving the processability of the battery plate and the cycle life of the battery. Therefore, they are favored by researchers and manufacturers.Common preparation methods for carbon nanotubes include arc discharge, laser evaporation and chemical vapor deposition [15][16][17] .…”