Kinetically Induced Memory Effect in Li-ion Batteries

Effective optimization and control of lithium-ion batteries cannot neglect the relation between fundamental physicochemical phenomena and performance. In this work, we apply a multi-step charging protocol to commercially relevant electrodes, such as LiNi0.8Mn0.1Co0.1O2 (NMC811), LiFePO4 (LFP), LiMn1.5Ni0.5O4 (LMNO), LiMn0.4Fe0.6PO4 (LMFP), Li4Ti5O12 (LTO) and Na3V2(PO4)3 (NVP), to investigate how the initial rate affects their kinetic response. Remarkably, electrodes undergoing phase separation exhibit a pronounced counter-intuitive memory effect under high-rate operating conditions. Using operando micro-beam X-ray diffraction, the origin is demonstrated to be embedded in the rate-dependent multi-electrode particle dynamics. Developed phase-field electrochemical models capture the ensemble behavior of electrode particles underlying the kinetically induced memory effect, establishing how the thermodynamics of the nanoscale (particle) level affects macroscopic battery behavior under realistic conditions. These results challenge established battery management strategies, opening the doors for improved characterization and optimization of fast-charging protocols, crucial in minimizing aging and heat production while enhancing energy efficiency and benefitting a wide range of battery-powered applications.