Rational Design of Thick Electrodes in Lithium‐Ion Batteries by Re‐Understanding the Relationship Between Thermodynamics and Kinetics

Abstract Tremendous efforts are made to enhance the energy density of lithium‐ion batteries, among which designing thick electrodes is a promising approach. Traditionally, kinetic effects are considered in constructing thick electrodes, such as decreasing the tortuosity to facilitate ion transport. This work innovatively investigates the coupling effect of kinetics and thermodynamics on electrode processes and conducts a competitive analysis between them by visualizing electrode processes. The results indicate that a sloping equilibrium potential curve facilitates the uniform utilization of electrodes, but severe kinetic constraints render the thermodynamic regulation ineffective. Thus, modifying the thermodynamic properties of the electrode to strengthen the regulatory effect is a promising approach. Kinetic constraints are the inherent factors limiting the capacity release of batteries. An in‐depth analysis reveals that ensuring the hybrid control of ions and electrons can significantly alleviate kinetic reaction heterogeneity. As a proof‐of‐concept, thick electrodes with vertical channels are constructed, enabling thermodynamics to regain dominance in the electrode process, ultimately achieving outstanding capacity retention of 63% at 4C. This work provides a more comprehensive perspective and represents a significant breakthrough in guiding electrode design to achieve a higher energy density.