Nanocellulose based carbon ink and its application in electrochromic displays and supercapacitors

Abstract

Conventional electronics have been highlighted as a very unsustainable technology; hazardous wastes are produced both during their manufacturing but also, due to their limited recyclability, during their end of life cycle (e.g. disposal in landfill). In recent years additive manufacturing processes (i.e. screen printing) have attracted significant interest as a more sustainable approach to electronic manufacturing (printed electronics). Despite the field of printed electronics addressing some of the issues related to the manufacturing of electronics, many components and inks are still considered hazardous to the environment and are difficult to recycle. Here we present the development of a low environmental impact carbon ink based on a non-hazardous solvent and a cellulosic matrix (nanocellulose) and its implementation in electrochromic displays (ECDs) and supercapacitors. As part of the reported work, a different protocol for mixing carbon and cellulose nanofibrils (rotation mixing and high shear force mixing), nanocellulose of different grades and different carbon: nanocellulose ratios were investigated and optimized. The rheology profiles of the different inks showed good shear thinning properties, demonstrating their suitability for screen-printing technology. The printability of the developed inks was excellent and in line with those of reference commercial carbon inks. Despite the lower electrical conductivity (400 S m−1 for the developed carbon ink compared to 1000 S m−1 for the commercial inks), which may be explained by their difference in composition (carbon content, density and carbon derived nature) compared to the commercial carbon, the developed ink functioned adequately as the counter electrode in all screen-printed ECDs and even allowed for improved supercapacitors compared to those utilizing commercial carbon inks. In this sense, the supercapacitors incorporating the developed carbon ink in the current collector layer had an average capacitance = 97.4 mF cm−2 compared to the commercial carbon ink average capacitance = 61.6 mF cm−2. The ink development reported herein provides a step towards more sustainable printed green electronics.

A Paper‐Based Triboelectric Touch Interface: Toward Fully Green and Recyclable Internet of Things

“…The ink preparation method and composition were previously reported in greater detail. [47] The nitrocellulose ink was prepared by first dissolving nitrocellulose blotting paper (GE Healthcare Life Science, No. 10600002) into acetone at a concentration of 80 mg ml −1 while stirring with a magnet bar.…”

Screen Printed Reflective Electrochromic Displays for Paper and Other Opaque Substrates

“…The performance of the novel rOECD architecture presented herein was compared to that of the conventional OECD. − For this, OECDs of both reverse and conventional architectures with two layers of the S V4 PEDOT:PSS ink were used (referred to as Type B displays). Figure shows the typical current vs time plots, recorded during the ON switch, for the conventional and reverse OECD and their change in color (recorded with a photodiode as described in the Experimental Section) during switching.…”

A Forest‐Based Triboelectric Energy Harvester

“…Softwood kraft lignin from the LignoBoost process was provided by RISE Bioeconomy and Health; dispersion-based pressure-sensitive adhesive (KIWOTHERM D123) was purchased from KIWO; the nanocellulosebased conductive carbon ink was prepared by RISE Research institutes of Sweden, and the method of preparation was previously reported. [58] Fiber Mat Preparation: The methods for electrospinning and conversion to carbon fibers were as previously reported. [45][46][47] In brief, high molecular weight fraction of softwood kraft lignin was dissolved in dimethyl formamide at a concentration of 47 wt%.…”

“…Softwood kraft lignin from the LignoBoost process was provided by RISE Bioeconomy and Health; dispersion‐based pressure‐sensitive adhesive (KIWOTHERM D123) was purchased from KIWO; the nanocellulose‐based conductive carbon ink was prepared by RISE Research institutes of Sweden, and the method of preparation was previously reported. [ 58 ]…”