Dissipative particle dynamics simulations of protein-directed self-assembly of nanoparticles*

The “shuttle effect” caused by the dissolution and migration of polysulfides during the charge-discharge process is believed to be one of the main reasons for rapid capacity fading and low Coulombic efficiency in lithium-sulfur batteries. Recently we have successfully designed and fabricated a protein-based nanofilter for effectively trapping polysulfides but facilitating the Li⁺ transport.  The nanofilter with unique porous structures is formed through a protein-directed self-assembly process and the surfaces are functionalized by the protein residues. In this work through dissipative particle dynamics simulations, we systematically investigate the self-assembly process of protein-coated nanoparticles. Mimicking the experimental conditions, we explore the effects from the coating materials (gelatin or polymer), surface coating density and solvent environments (water or acetic acid/water mixture), on the resulting porous structures. Our results demonstrate that consistent with experimental observations the final structures are highly dependent on above conditions. The simulations may provide guidelines for further improvement of nanofilter and eventually lead to better performance of lithium-sulfur batteries.