Electrode Engineering with CNTs to Enhance the Electrochemical Performance of LiNi0.6Co0.2Mn0.2O2 Cathodes with Commercial Level Design Parameters. Issue 12 (11th May 2020)

• Record Type: Journal Article
• Authors: Kim, Dong Won; Hwang, Soo Min; Yoo, Ji Beom; Kim, Young‐Jun
• Is Part Of: ChemElectroChem. Volume 7:Issue 12(2020)
• Page Start: 2621
• Page End: 2628
• Publication Date: 2020-05-11
• Subjects: CNT -- lithium-ion batteries -- Ni-rich cathodes -- rate capability -- pulse measurement -- ToF-SIMS; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202000283
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: Electrode engineering is considered an essential step toward fabricating advanced Li‐ion batteries (LIBs). Conducting agents play a critical role in determining both the electron conduction and Li‐ion transport in electrodes and thus in enhancing battery performance. Here, we report the effect of carbon nanotube (CNT) addition on the electrochemical properties of LiNi0.6 Co0.2 Mn0.2 O2 (NCM622) cathodes. By varying the CNT content from 0 to 2 wt% in the total weight percentage (2 wt%) of conducting agents containing carbon black, the rate capability and cycling performance are examined. The limiting factors affecting the electrochemical performance are probed by using electrochemical impedance spectroscopy and pulse polarization measurements. The results show that as the CNT content increases, the electrical conductivity of the electrode decreases and the porosity increases. The addition of 1 wt% CNT gives rise to the best rate and cycling properties for the NCM622 electrodes. The pulse measurements reveal that the CNT addition mitigates the concentration polarization upon charging/discharging at high current rates owing to the evolved micrometer‐scale pores in the electrodes, thereby leading to better rate capability. The post‐mortem analysis on the electrodes discharged at a high current rate by time‐of‐flight secondary ion mass spectroscopy mapping show that the CNT addition allows facile Li‐ion transport from the electrolyte side into the NCM lattice, even in the vicinity of the bottom region (current collector side), which strongly corroborates the pulse polarization results. These findings suggest that the use of CNTs as a conducting agent is effective in improving the electrochemical performance of Ni‐rich cathodes. Abstract : Efficacy of CNTs : The effect of carbon nanotubes (CNTs) as conducting agent on the electrochemical performance of LiNi0.6 Co0.2 Mn0.2 O2 cathodes is investigated. The combinatorial use of CNTs and carbon black improves the cycling stability and rate capability.