Inkjet printed microsupercapacitors on paper

By on October 27, 2021 0


Technologies such as the Internet of Things (IoT) and portable and portable electronics provide applications for multiple industries. However, with the growth of these technologies comes a huge problem: the increasing amount of electronic waste. An article in the journal Advanced functional materials considers the urgent need for environmentally friendly electronics that can be eliminated at the end of their lifecycle with minimal environmental impact.

To study: Disposable micro-capacitors on high-speed inkjet printed paper. Image Credit: Chaikom /

Micro-capacitors on paper – A solution to the growing problem of electronic waste

Paper-based microsupercapacitors (MSCs) have generated great research interest as a solution to the problem of large-scale e-waste. Due to their long lifespan, high power density, and fast charge rate, MSCs are particularly attractive candidates for miniaturized electronics and intelligent self-powered systems.

MSCs on paper are even more attractive due to their respect for the environment, their capacity for renewal and their profitability.

However, this respect for the environment comes at the expense of electrochemical performance. This is especially true of the MSC’s throughput capacity on paper. The development of MSCs on paper with high electrochemical performance is a major axis in the field of microelectronics. Achieving both will create truly environmentally friendly and highly reliable electronics for a variety of important applications.

Making the manufacturing process more sustainable with inkjet printing

Disposable alone is not enough to create truly environmentally friendly MSCs; it is also necessary to pay attention to the manufacturing process. Traditional manufacturing processes use chemicals and solvents that are toxic and harmful to the environment as well as fossil fuels used to make the components. They also create huge amounts of waste and release toxic byproducts into the environment.

Characterization of PDG inks. a) Photograph of PDG ink, b) zeta potential and c) DLS particle size distribution of PEDOT: PSS, PEDOT: PSS / GQD, PEDOT: PSS / EEG, and PDG ternary dispersions in the water / EG mixture (ratio of volume 2: 1), d) photograph of PDG patterns printed on photo paper, e, f) SEM images of PDG patterns printed on photo paper, g, h) TEM images of PDG ink. Image credit: Zheng Li et al., Advanced Functional Materials, Wiley.

One sustainable manufacturing technique under study is inkjet printing. The benefits that make inkjet printing an attractive alternative include minimal material waste, scalability, pure additive processing, no-mask pattern, and compatibility with many active materials and substrates.

Paper – A superior substrate for inkjet printing

Paper is a superior substrate due to its compatibility with inkjet printing. This is due to its hierarchical structure made of cellulose fibers. It is porous, has a rough surface texture, and its capillaries facilitate superior absorption of ink patterns, leading to the rapid formation of printed patterns.

However, there are several challenges with inkjet printing and paper that need to be ironed out. First of all, inkjet printing makes it possible to create fine patterns with high resolution, but MSCs require thick electrode patterns (this increases the surface performance).

Second, the paper is not compatible with non-volatile or aggressive solvents due to high absorption. Finally, the paper is vulnerable to post-treatments such as high temperature sintering.

These factors make it difficult to fabricate highly conductive patterns on paper substrates with inkjet printing techniques, which means that throughput performance is affected. This makes it difficult to make commercially viable paper MSCs.

A new way to make MSCs on environmentally friendly paper with high electrochemical performance

In a new study in Advanced functional materials, a simple and reliable inkjet printing technique for creating MSCs on environmentally friendly paper with superior electrochemical performance (such as capacity rates of 84% after 4 months) has been demonstrated.

The research team has developed environmentally friendly, binder-free conductive inks based on the ternary composite of PEDOT: PSS, graphene quantum dots (GDQ) and electrochemically exfoliated graphene (EEG), dispersed in a water solvent. / ethylene glycol. Both GDQ and EEG stabilized the PEDOT: PSS based ink and significantly improved the throughput capability of the MSCs.

The resulting ink is very stable, facilitating reliable and efficient printing of an MSC on paper.

a) Photograph of an MSC printed on photo paper for flexibility performance test, b) CV curves at 1000 mV s-1 and c) surface capacitance of the MSC under different mechanical radii of curvature, d) photograph of a fully printed MSC array with four MSCs connected in series on cardboard paper, e) CV curves at 1000 mV s-1 and f) GCD curves at 10 µA of the series-connected MSC matrix, g) photograph of a fully printed MSC matrix with four MSCs connected in parallel on cardboard, h) CV curves at 1000 mV s-1 and i) GCD curves at 200 µA of the MSC network in parallel connection. All MSCs are printed in 10 passes. In (g), the bus lines are printed with 17 passages. Image credit: Zheng Li et al., Advanced Functional Materials, Wiley.

Manufacturing the MSC is simple, with just two steps: printing the electrodes and pouring the electrolytes.

The printer used for electrode printing was the Diamatic Materials printer from Fujifilm Inc. The printer used 10 µl cartridges and the paper used was commercially available paper from Staples as well as Korsnäs cardboard paper. . The ink was allowed to dry before printing the next layer to avoid warping, and the final paper was air dried.

Each MSC was then treated with a simple electrolyte, a mixture of poly (styrenesulfonic acid) and H3Purchase order4. After drying overnight in a hood, the MSCs were characterized electrochemically. TEM samples were prepared for material characterization. A life cycle assessment was carried out with the SimaPro software. GWP and ecotoxicity were studied with the IPCC 2013 GWP 100a and ECO-indicator 99 (H) methods.

Life cycle assessment results of PDG MSCs (10 print passes) and MXene-based paper MSCs. a) ecotoxicity, b) global warming potential (GWP), c) standardized ecotoxicity, and d) standardized PRP for the three types of paper MSCs taking into account the complete device, electrode ( including paper substrate and current collectors), and electrolyte only, respectively. In (c, d), the normalization is greater than the maximum energy that can be stored by the MSCs. Image credit: Zheng Li et al., Advanced Functional Materials, Wiley.

Data collected from electrochemical and material characterization as well as ecotoxicity and GWP potential demonstrated favorable results for inkjet printing of environmentally friendly and reliable MSCs with this method.

The future

Paper-based MSCs have enormous potential to advance the field of electronics towards a sustainable future. Research such as the study presented in this article is helping to develop truly environmentally friendly microsupercapacitors that can be easily disposed of at the end of their lifecycle, with the performance needed to make them commercially viable.

Further reading

Li, Z et al. (2021) Inkjet Printed High Throughput Paper Disposable Microsupercapacitors [online] Advanced functional materials. Available at:

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