Effect of component content variation on composition and structure of activated carbon in PVDF:K₂CO₃

Abstract

Percolative composites consisting of potassium carbonate dispersed in polyvinylidene fluoride (PVDF) polymeric matrix have shown high dielectric constant and electrical conductivity due to the formation of chemically activated carbon interfaces in the composite. In this paper, a series of PVDF/K2CO3 films with different component contents were prepared and investigated by Raman and X-ray photoelectron spectroscopies to clarify chemical composition, structure and formation mechanism of activated carbon. The results revealed the presence of a reaction loop to consume both constituent phases and the formation of sp2 carbon rings in the yielded activated carbon due to cross-linking dehydrofluorination of PVDF during thermal treatment. The sp2 content showed a non-linear dependence on K2CO3 content with the presence of an optimal value corresponding to the highest dielectric constant and electrical conductivity. This study thus can give a direction for future fabrication of PVDF/K2CO3 electrode materials for supercapacitors.