Hyperpolarized129Xe Nuclear Magnetic Resonance Studies of Si Nanocomposite Electrode Materials

Abstract

Porosity and interconnectivity of pores play an important role in the performance of composite electrodes in Li ion batteries. Hyperpolarized (HP) 129Xe nuclear magnetic resonance (NMR) is powerful for probing porosity and interconnectivity of nanopores. This study represents the first time that temperature-dependent HP 129Xe NMR has been successfully applied to explore the pore structure and interconnectivity in composite electrodes made of nano Si powder, super P carbon, and sodium carboxyl methyl cellulose (CMC) binder. In particular, this work focuses on the influence of the binder content on the porosity and pore interconnectivity in Si composite electrode (Si + C):CMC materials. Our data from HP 129Xe NMR spectra show that the CMC content has an effect on the porosity and pore interconnectivity of Si nanocomposite electrode materials. We determined parameters, such as pore size, heat of adsorption, and characteristic chemical shift, of (Si + C):CMC samples based on the temperature-dependent HP 129Xe...