Low-Tortuosity Thick Electrodes with Active Materials Gradient Design for Enhanced Energy Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Modern society's increasing energy demands necessitate advanced battery technologies.
• Optimizing electrode microstructures is crucial for high-energy-density batteries.
• Low-tortuosity architectures improve charge transport in thick electrodes, but heterogeneity persists.

Purpose of the Study:

• To engineer an active material gradient in low-tortuosity electrodes to address uneven reaction kinetics.
• To compensate for nonuniform lithiation/delithiation processes in thick battery electrodes.
• To enhance electrochemical mass transport and improve rate capabilities in high-loading electrodes.

Main Methods:

• Fabrication of low-tortuosity electrodes with a gradient of active material concentration.
• Electrochemical characterization to evaluate electrode performance and kinetics.
• Computational simulations to elucidate the effect of the active material gradient architecture.

Main Results:

• The active material gradient effectively reduces integrated ion diffusion distance.
• Accelerated electrochemical reaction kinetics were observed due to the gradient.
• Electrodes achieved high mass loading (60 mg cm^-2) with enhanced rate capabilities.
• The combined low-tortuosity and gradient structure significantly improved battery performance.

Conclusions:

• The active material gradient architecture is a viable strategy for optimizing thick electrodes in high-energy batteries.
• This approach mitigates heterogeneous mass transport and improves electrochemical performance.
• The findings provide insights for designing next-generation batteries with high energy and power densities.