Imidazole-doped nanocrystalline cellulose solid proton conductor: synthesis, thermal properties, and conductivity

J Tritt-Goc,R Pankiewicz,I Jankowska,K Pogorzelec-Glaser,P Ławniczak

doi:10.1007/s10570-017-1555-8

Abstract

A new proton conducting material with a possible application as a membrane in fuel cells is synthesized. It is formed by nanocrystalline cellulose (NCC) doped with a different concentration of the imidazole molecules (Im) used as “dry” conducting species. The nanocomposites (NCC-Im) are obtained in the form of films. Their chemical composition, thermal properties, and the electric conductivity are determined by elementary and thermogravimetric analysis, differential scanning calorimetry and impedance spectroscopy methods, respectively. The nanocomposite (1.7NCC-Im) with the highest concentration of imidazole i.e. one Im per 1.7 glucose unit shows the highest electrical conductivity equal to 2.7 × 10−2 S/m at 140 °C. This value is about five orders of magnitude higher than that of the pure NCC film at this same temperature. The important feature is that it is obtained for nanocomposite under anhydrous conditions.

Highlights

The development of inexpensive, easy in production, flexible, solid-state, and sustainable energy producing materials is essential to meet a predicted increase in energy consumption in today’s society and protect the environment
The successful synthesis of biodegradable polymeric composite of microcrystalline cellulose doped with imidazole (Smolarkiewicz et al 2015, 2016; Zhao et al 2016) was an inspiration for the work presented in this paper
Starting these studies we have formulated the following research hypotheses: (1) replacement of cellulose raw material by nanocrystalline cellulose will enable more effective functionalization of nanocellulose surface by the heterocycles molecules and will increase the proton conductivity, (2) the application of the heterocyclic nitrogencontaining molecules as conducting species will lead to nanocomposites with proton conductivity in the intermediate temperature range, higher than 100 °C

Summary

Introduction

The development of inexpensive, easy in production, flexible, solid-state, and sustainable energy producing materials is essential to meet a predicted increase in energy consumption in today’s society and protect the environment Such materials can find application in a variety of electrochemical devices including fuel cells which are of special interest because they permit clean and direct conversion from the chemical to electrical energy (Devanathan 2008; Sharaf and Orhan 2013; Zhang et al 2015; Hu et al 2017). Nafion which is most commonly used as PEM in fuel cells is relatively expensive and its production is a challenge

Methods

Results

Conclusion