Co-free gradient lithium-rich cathode for high-energy batteries with optimized cyclability

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-rich layered oxides (LLOs) are promising for high-energy battery cathodes.
• Voltage decay due to irreversible reactions at high voltages hinders LLO application.

Purpose of the Study:

• To investigate the electronic structure of Mn-based LLOs.
• To design and synthesize novel cobalt-free, concentration-gradient LLOs (CF-CG-LLOs) to overcome voltage decay.

Main Methods:

• Theoretical study of molecular orbitals in Mn-based Li-rich configurations.
• Synthesis of cobalt-free concentration-gradient LLOs.
• Electrochemical testing of pouch cells.

Main Results:

• Identified stable redox reactions in LiMn6 structures and the disruptive effect of Cobalt.
• CF-CG-LLOs exhibited exceptional capacity retention over 100 cycles.
• Achieved ultra-low voltage decay (0.15 mV/cycle) and high Coulombic efficiency (99.86%).

Conclusions:

• Cobalt removal and concentration gradients are key to stabilizing LLO cathodes.
• CF-CG-LLOs offer a viable pathway for low-cost, high-energy-density batteries.
• This approach addresses critical challenges in next-generation battery technology.