| Abstract Scope |
Battery porous electrodes contain numerous redox-active particles with uneven current distributions, a crucial factor for understanding battery safety, performance, and electrochemical behavior. While imaging methods can measure the particle state of charge, they cannot directly measure electrochemical currents. In this study, we utilize a recently developed microelectrode array to quantify current distribution among multiple parallel-connected battery particles. We combine a single-battery particle cycling system with a parallel data acquisition setup to cycle up to 16 particles simultaneously. This allows us to monitor the electrochemical current flow into each battery particle in situ with a temporal resolution under 1 second and a current resolution below 1 pA. We apply this method to both phase-transforming LiCoO2 (LCO) and solid-solution Li(Ni, Mn, Co)O2 (NMC), revealing that cycling rate, charge/discharge direction, phase transformation, and particle cracking affect current distribution. These findings can guide the design of next-generation batteries with enhanced safety and performance. |