Scientists have engineered a new cathode material that could significantly advance the development of fast-charging lithium metal batteries. The research, published in Nature Communications, introduces an entropy-increased version of lithium manganese oxide (LiMn2O4), commonly known as LMO.
The novel material, dubbed EI-LMO, was created by incorporating small amounts of copper, magnesium, iron, zinc, and nickel into the standard LMO structure. This multi-element doping strategy results in a disordered cation distribution and a contracted lattice structure, which enhances the material’s performance in high-current applications.
Key advantages of EI-LMO include:
- Improved cycling stability: EI-LMO electrodes retained 80% of their capacity after 1000 cycles at a high current of 1.48 A/g, compared to only 61% for standard LMO.
- Suppression of phase transitions: The entropy-increasing approach effectively mitigates the problematic two-phase transition typically observed in LMO during charging.
- Enhanced structural integrity: While standard LMO undergoes plastic deformation during cycling, EI-LMO exhibits elastic deformation, helping to maintain stable lithium diffusion channels.
- Strengthened chemical bonds: The entropy increase reinforces Mn-O bond strength and enhances overall lattice elasticity.
The researchers found that these improvements stem from the material’s ability to undergo elastic stress release and smooth charge compensation during cycling. Additionally, the disordered cation distribution helps stabilize the three-dimensional lithium-ion diffusion channels within the structure.
This breakthrough could have significant implications for the development of extreme fast-charging protocols in lithium-based batteries. The entropy-increased doping strategy may also be applicable to other cathode materials, potentially opening new avenues for enhancing fast-charging capabilities across various battery chemistries.
As the demand for rapid-charging electric vehicles and portable electronics continues to grow, innovations like EI-LMO could play a crucial role in overcoming current limitations in battery technology.
Source: Nature Communications
