Probing Electrical Degradation of Lithium Ion Battery Electrodes with Nanoscale Resolution

The investigation of the electrical conductivity evolution during cycling can lead to a better understanding of the degradation in electrode materials for Li-ion batteries (LIBs). In this study, we probed the electrical degradation of LIB electrodes with nanoscale resolution via quantitative and comparative scanning spreading resistance microscopy (SSRM). First, the electrical degradation of cathode materials, LiNi_0.8Co_0.15Al_0.05O₂ (NCA), was studied [1]. After 300 charge/discharge cycles, stepwise-increasing resistance distributions toward the centers of the secondary particles were observed. Second, the electrical degradation of LIB anodes, the blended Si-C composites with graphite (Gr) particles, was investigated using SSRM [2]. From the SSRM measurements, it was obviously demonstrated that the electrical conductivity of the Si-C composite particles is considerably degraded by 300 cycles of charging and discharging, although the Gr particles maintain their conductivity. Our approach using SSRM technique can be an effective method to study the nanoscale electrical properties of various LIB electrode materials.

[1] S.Y. Park et al., Nano Energy 49, 1–6 (2018).
[2] S.H. Kim et al., ACS Appl. Mater. Interfaces, 10, 24549-24553 (2018).