Enhancing electrode wettability in lithium-ion battery via particle-size ratio control

Enhancing the electrolyte wetting has been claimed to be a great challenge in developing high-energy density and large-scale lithium-ion batteries (LIBs). Superb wettability ensures high-quality LIBs, but poor wettability incurs unstable capacity, shortened cycle life, and additional manufacturing cost. However, wettability issue has been understated so far, and associated breakthrough technology is not yet available. Here, we report the enhancement of electrode wettability by controlling the volume ratio of different-sized particles. We demonstrate the electrolyte transport behavior in a straightforward way, and investigate the effect of particle-size ratio on the cathode wettability in two aspects: with porosity preserved and by adding small particles. Results show that particle-size ratio and porosity greatly influence the electrode wettability. Electrolyte distribution and correlated pore-throat size distribution not only affect the wetting behavior but also pose crucial factors that determine the wetting speed. This study provides novel mechanistic insight into the electrolyte wetting process, and the results are one of the few published ones that give important information toward wettability enhancement.