Key parameters governing the reversibility of Si/carbon/CMC electrodes for Li-ion batteries

TLDR: In this paper, a self-healing process of the Si−CMC hydrogen bonding which can accommodate textural stresses and can evolve during cycling is proposed to be critical for Si-based electrode performances.

Abstract: Various Si/carbon/polymer composite electrodes were prepared to better understand the influence of the Si−polymer interactions on the stability of the Li−Si reaction and especially the superior performances of CMC-based (carboxy−methyl−cellulose) composites despite the large volume changes of the Si particles upon cycling. Via the modification of the composites formulation, the nature of the polymer, the nature and the amount of the substituting groups and the surface chemistry of the Si particles, together with the use of various characterization techniques (TEM, SEM, NMR−MAS, infrared spectroscopy, TGA, etc.) we could propose that the performances of the Si/Csp/CMC composite electrodes are nested in both the porous texture of the electrode and in the nature of the Si−polymer chemical bonding. A self-healing process of the rather strong Si−CMC hydrogen bonding which can accommodate textural stresses and can evolve during cycling is proposed to be critical for Si-based electrode performances. This better ...