From Fundamental Understanding to Engineering Design of High-Performance Thick Electrodes for Scalable Energy-Storage Systems

The ever-growing needs for renewable energy demand the pursuit of batteries with higher energy/power output. A thick electrode design is considered as a promising solution for high-energy batteries due to the minimized inactive material ratio at the device level. Most of the current research focuses on pushing the electrode thickness to a maximum limit; however, very few of them thoroughly analyze the effect of electrode thickness on cell-level energy densities as well as the balance between energy and power density. Here, a realistic assessment of the combined effect of electrode thickness with other key design parameters is provided, such as active material fraction and electrode porosity, which affect the cell-level energy/power densities of lithium–LiNi_0.6Mn_0.2Co_0.2O₂ (Li–NMC622) and lithium–sulfur (Li–S) cells as two model battery systems, is provided. Based on the state-of-the-art lithium batteries, key research targets are quantified to achieve 500 Wh kg^–1/800 Wh L^–1 cell-level energy densities and strategies are elaborated to simultaneously enhance energy/power output. Furthermore, the remaining challenges are highlighted toward realizing scalable high-energy/power energy-storage systems.