Core–Shell Hybrid Nanowires with Protein Enabling Fast Ion Conduction for High-Performance Composite Polymer Electrolytes

Abstract

Incorporating nanofillers is one of the promising approaches for simultaneously boosting the ionic conductivity and mechanical properties of solid polymer electrolytes (SPEs). However, effectively creating faster ion-conduction pathways via nanofillers still remains a big challenge. Herein, core–shell protein–ceramic nanowires for more efficiently building fast ion-conduction networks in SPEs are reported. The core–shell protein–ceramic nanowires are fabricated via in situ growth of protein coating on the electrospun TiO2 nanowires in a subtly controlled protein-denaturation process. It is demonstrated that the core–shell protein@TiO2 nanowires effectively facilitate ion-conduction. As a result, the ionic conductivity, mechanical properties, electrochemical stability, and even Li+ transference number of the SPEs with core–shell protein@TiO2 nanowires are significantly enhanced. The contributions from the 1D morphology of the protein@TiO2 nanowires, and more importantly, the favorable protein structure for further promoting ion-conduction at the polymer–filler interfaces are analyzed. It is believed that the protein plays a pivotal role in dissociating lithium salts, which benefits from the strong interactions between protein and ions, making the protein serve as a unique “natural channel” for rapidly conducting Li+. This study initiates an effective method of promoting ionic conductivity and constructing faster ion-conduction networks in SPEs via combining bio- and nanotechnology.