Intercalation reactions modify the charge density in van der Waals (vdW) materials through coupled electronic-ionic charge accumulation, and are susceptible to modulation by interlayer hybridization in vdW heterostructures. Here, we demonstrate that charge transfer between graphene and α-RuCl3, which dopes the graphene positively, greatly favors the intercalation of lithium ions into graphene-based vdW heterostructures. We systematically tune this effect on Li+ ion intercalation, modulating the intercalation potential, by using varying thicknesses of hexagonal boron nitride (hBN) as spacer layers between graphene and α-RuCl3. Confocal Raman spectroscopy and electronic transport measurements are used to monitor electrochemical intercalation and density functional theory computations help quantify charge transfer to both α-RuCl3 and graphene upon Li intercalation. This work demonstrates a versatile approach for systematically modulating the electrochemical intercalation behavior of two-dimensional layers akin to electron donating/withdrawing substituent effects used to tune molecular redox potentials.
@article{arxiv.2308.06437,
title = {Modulating the electrochemical intercalation of graphene interfaces with $\alpha$-RuCl$_3$ as a solid-state electron acceptor},
author = {Jonathon Nessralla and Daniel T. Larson and Takashi Taniguchi and Kenji Watanabe and Efthimios Kaxiras and D. Kwabena Bediako},
journal= {arXiv preprint arXiv:2308.06437},
year = {2023}
}