Gradient Design with Low-Tortuosity Overcoming Kinetic Limitations in High-Loading Solid-State Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Commercialization of solid-state batteries (SSBs) is hindered by limitations in thick cathode performance.
• Tortuous ion transport pathways and slow solid-solid diffusion in thick cathodes impede electrochemical kinetics and limit capacity at high current densities.

Purpose of the Study:

• To develop a novel cathode structure for high-loading solid-state batteries that enables fast charging.
• To overcome kinetic limitations in thick cathodes by improving ion transport and mitigating concentration gradients.

Main Methods:

• Design and fabrication of a conductivity gradient cathode with low-tortuosity ion pathways.
• Electrochemical testing of LiNi_0.8Co_0.1Mn_0.1O₂ and LiFePO₄ cathodes under various current densities.
• Evaluation of room-temperature (RT) capacities and areal capacities.

Main Results:

• LiNi_0.8Co_0.1Mn_0.1O₂ cathodes achieved RT capacities of 147 mAh g^-1 at 5C and 110 mAh g^-1 at 10C.
• A RT areal capacity of 3.3 mAh cm^-2 was achieved at 3C for LiNi_0.8Co_0.1Mn_0.1O₂ cathodes.
• The conductivity gradient strategy demonstrated universality in LiFePO₄ cathodes.

Conclusions:

• The proposed conductivity gradient cathode design effectively enhances ion transport and enables fast charging in thick solid-state battery cathodes.
• This approach facilitates simultaneous high energy and power densities in SSBs.
• The strategy offers a promising solution for the large-scale application of high-loading solid-state batteries.