One of the critical factors influencing the performance of graphite anodes is the uniformity of the coating thickness. Despite advances in manufacturing processes, non-uniform coating thickness remains a significant challenge, leading to issues such as non-uniform lithiation, mechanical stress, and delamination.
- Non-Uniform Lithiation: If the coating thickness is not uniform, the lithiation (insertion of lithium ions) process can become uneven across the graphite anode. Thicker regions may experience higher local stresses and strains during lithiation and delithiation, leading to accelerated degradation and reduced battery life.
- Mechanical Stress and Cracking: Variations in coating thickness can create mechanical stress concentrations during the charge-discharge cycles. These stresses can cause cracking and mechanical failure of the graphite anode. Cracks can disrupt the electronic connectivity within the anode and lead to capacity loss.
- Thermal Management: Uneven coating thickness can affect the thermal properties of the anode. Regions with thicker coatings may have different thermal conductivity compared to thinner regions, leading to uneven heating during operation. This can exacerbate thermal runaway risks and impact battery safety.
- Ion Transport Resistance: The thickness of the coating affects the ion transport resistance. Inconsistent thickness can create areas with higher resistance, which can impede the efficient transport of lithium ions and reduce the overall performance and efficiency of the battery.
Addressing these issues requires precise control over the coating process to ensure a uniform and optimal thickness across the entire surface of the graphite anode.
