Structural features and electrochemical behavior of amino acid-based biocomposites

The approach associated with the use of active organic components in the formation of the electrode composition is a new and promising solution for improving hybrid electrochemical systems. In this manuscript, we aim to determine the influence of the type of carbon template and the structural ordering of components during mechanosynthesison the manifestation of the electroconductivity and electrochemical properties of amino acid-based biocomposites. To achieve this, a series of biocomposites based on thermally expanded graphite (TEG) and carbon nanotubes (CNTs) and amino acids, like aspartate and glycine were fabricated and tested. Impedance spectroscopy has revealed that all the synthesized biocomposites exhibit an electronic conduction mechanism, with primary contribution to conductivity originating from the carbon templates. Direct observations have revealed that in the case of biocomposites with TEG, the template undergoes significant cracking and dispersion, leading to the formation of a mixture of TEG and amino acid particles. For biocomposites with CNTs, dispersion is comparatively less and uniform covering of compacted nanotube aggregates by amino acid particles is observed. The different structural organization of components in the biocomposites determines their electrochemical behavior in a three-electrode cell with a proton KOH electrolyte. Biocomposites with CNTs, due to the presence of surface-localized amino acids as centers of electrochemical reactions, exhibit pseudocapacitive charge accumulation. For biocomposites based on TEG, the disordered arrangement of components and the lack of stable conductivity contacts between amino acids and the template leads to capacitive charge accumulation through the formation ofthe electrical double layer.