Challenges in lithium-ion batteries: modelling tools to overcome performance and sustainability limitations

Nowadays, the spread of electric vehicles powered by lithium-ion batteries leads the world's transition to transport electrification. However, several critical challenges hinder lithium-ion batteries' practical and sustainable utilisation. Performance-wise, electric vehicles should be recharged at the speed comparable to traditional vehicles. However, such fast charging is not possible without strong degradations resulting in rapid ageing of the battery system due to the presence of mesoscopic electrochemical phenomena occurring at the anode, given the sluggish intercalation of lithium within a phase-separating material like graphite. Sustainability-wise, the increasing demand for lithium-ion batteries, with the lack of critical raw materials and the disposal of end-of-life batteries, is driving toward using recycled cathode active materials in the next generation of batteries. However, recycled cathode materials from closed-loop solutions might have a lower quality than those prepared from fresh precursors, which translates into lower electrochemical properties. We show that all these critical challenges can be quantitatively addressed through a physics-based multiscale modelling approach for lithium-ion battery research. The mesoscopic model [1,2] validated against fast charge in-operando optical experiments (Figure 1) can predict the distribution of graphite's state of lithiation into the electrode thickness and the particles' radius (solid/dashed lines), thus unravelling the interplay among phase separation and degradation phenomena. By linking the mesoscopic model to equivalent circuit models, we perform characteristic time analysis during relaxation, predicting the system dynamics of physical phenomena to detect any early signal of degradation efficiently [3]. Lastly, we propose compensatory measures to develop cathodes with recycled active materials (Figure 2). Based on full cell macro-homogeneous model simulations validated against commercial cell data, we define design solutions to overcome the performance limitations of recycled Li-ion battery materials [4].