Electrochemical Bridging-Impact Method for Characterizing the NCA@Carbon Core–Shell Cathode

Abstract

Carbon-based core–shell (CBCS) materials have received considerable and could be the next generation of cathode materials for high energy density lithium-ion batteries (LIBs). The carbon shell provides a large interfacial area between active-material core and electrolyte for charge transport and shortened diffusion path for intercalation/de-intercalation of active species. In order to achieve high performance of CBCS cathode, tuning diffusion path is required via varying the shell-thickness. Herein, Li-Ni-Co-Al Oxide/Carbon (NCA/C) core-shell is prepared with varying shell thickness within the range of ca. 0.1 to 0.5 µm. In order to study the electrical properties of CBCS, we use the “Electrochemical Bridging-Impact”1 , 2 methodology along with a molecular dynamics (MD) simulation to investigate the ion communication between the solid-liquid interface. The bridging-impact is used to determine the contact resistance across the individual particle contact via measuring the current magnitude resulting from the arrival particle contacting with the supporting electrode can be investigated fundamental electrical properties, i.e., contact resistance and zero charge potential of the materials. Ion diffusion (Li+) between solid (inner-core NCA towards porous carbon shell) and liquid interface can be simulated via MD. The result depends on the thickness of the carbon layer, which should be tuned the electrical contact and ion communication between the solid-liquid junction. This study should be a guide rational design of practical core-shell materials.