Probing electrical degradation of cathode materials for lithium-ion batteries with nanoscale resolution

• Published in: Nano energy Vol. 49; pp. 1 - 6
• Main Authors: Park, Seong Yong, Baek, Woon Joong, Lee, Seung Yeon, Seo, Jin Ah, Kang, Yoon-Sok, Koh, Meiten, Kim, Seong Heon
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2018
• Subjects: LiNixCoyAlzO2; Lithium-ion battery; Microcrack; SSRM; Lithium-ion battery; Microcrack; LiNixCoyAlzO2; SSRM
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2018.04.005

Understanding the degradation mechanism of Lithium-ion batteries (LIBs) is critical in developing high-performance LIBs, and the investigation of their electrical conductivity evolution during cycling can lead to a better understanding of the degradation mechanism of the cathode materials for Li-ion batteries (LIBs). Here, we studied the evolution of the electrical conductivity of LiNi0.8Co0.15Al0.05O2 (NCA) particles for LIB cathodes using scanning spreading resistance microscopy (SSRM). After 300 charge/discharge cycles, stepwise-increasing resistance distributions toward the centers of the secondary particles are observed. These distributions correspond to the degenerated granular structures of the secondary particles caused by the formation of microcracks. In addition, the correlation between the electrical conductivity and microstructure of the NCA cathode is established to explain the observed decay of the NCA discharge capacity. Our findings can provide an insight into the debatable degradation mechanism of LIB cathode materials such as NCA and NMC (LiNixMnyCozO2, x + y + z = 1). [Display omitted] •The electrical degradation in secondary LiNi0.8Co0.15Al0.05O2 (NCA) particles was visualized with nanoscale resolution.•After 300 charge/discharge cycles, stepwise-increasing resistance distributions within the secondary particles were observed.•These distributions corresponded to the degenerated granular structures of the secondary particles caused by micro-cracks.