Chemical origins of a fast-charge performance in disordered carbon anodes

Fast charging of lithium-ion cells often causes capacity loss and limited cycle life, hindering their use in high-power applications.  This paper* by researchers from Happy Electron Carbon Supecap Ltd, the University of Pisa, this department, the University of Warwick, and the University of Nottingham, employed electrochemical analysis and a multiphysics model to identify and quantify chemical and physical constraints during fast charging.  They compared state-of-the-art graphite and nanocluster carbon (nC, a disordered carbon) anodes.

The combination of modeling, material phase separation phenomena with ion-electron transfer theory revealed significant insight.  The active material strongly influenced charge transfer kinetics and solid-state lithium diffusion.  Unlike graphite, nC supports lithium insertion without phase separation, enabling faster lithium diffusion, better volume utilisation, and lower charge transfer resistance.

In the paper the researchers demonstrate practical implications of these material phenomena through multilayer pouch cells made with nC anodes, which withstand over 5,000 fast-charge cycles at 2C without significant degradation (<10% at reference 0.2C).

*'Chemical origins of a fast-charge performance in disordered carbon anodes', published by ACS Applied Energy Materials.