Interface strength of silicon with surface engineered 2D-materials

Beyond commercial solar cells, silicon is now venturing into EV applications due to its high electrochemical potency. However, battery technology cannot rely on silicon alone as it suffers from stress-mediated mechanical failures and requires additives to combat stresses in the electrode architecture. 2D-materials such as graphene and transition metal carbides (MXenes) are the two most promising additives which besides providing mechanical stability to silicon electrode, also impart flexibility and improved electrochemical performance. Thus, to realize these combinations at the commercial level, it is critical to understand the important characteristics of the interface formed between them. We use Density functional theory (DFT) to calculate the strength of silicon-graphene and silicon-MXene interfaces. Most importantly, our work focuses on understanding the variation of interface strength between silicon and 2D materials as surface functional groups on later are altered. A comprehensive analysis of surface chemistry and electron redistribution at the interfaces is also presented to better describe the physio-chemical phenomenon impacting the changes in interface strength.