SWNT Networks with Polythiophene Carboxylate Links for High-Performance Silicon Monoxide Electrodes

Abstract

Carboxylated polythiophenes, such as poly[3-(potassium-4-butanoate) thiophene] (PPBT), play a critical role in securely connecting single-walled carbon nanotube (SWNT) electrical networks onto the surface of carbon-coated silicon monoxide (c-SiOx). These connections are a function of the materials’ surface chemistries and resultant physical/chemical bonding through favorable molecular interactions. Specifically, the PPBT π-conjugated backbone and alkyl side chain carboxylate moieties (COO−), respectively, physically interact with the SWNT and c-SiOx carbon layer π-electron-rich surfaces, and chemically bind to surface hydroxyl (−OH) species of the c-SiOx electroactive materials to form a carboxylate bond. This approach effectively captured pulverized particles that form during battery operation and beneficially suppressed the thickness change that electrodes typically undergo. The resultant electrodes exhibited superior electrochemical performance, which was ascribed to stable SEI layer formation, reduced...