Researchers at the Department of Electronics and Computer engineering at Binghamton State University in the United States have developed a disposable paper battery that integrates bacteria into paper and generates electricity through bacteria.
Figure ∣ Source: Seokheun Choi
Seokheun Choi, an assistant professor at the team, says Paper-based Electronics have a unique advantage, which is flexible, sustainable, environmentally friendly, inexpensive, and has good mechanical, dielectric and fluid properties. Micro-electronics and batteries can provide power for a wide variety of devices, such as the intake of medical devices, intelligent transport sensors and so on.
The rapid development of micro-electronic products and batteries has led to innovation in the design of electronic equipment and more attention to its environmental protection. It is estimated that more than 50 billion of electronic equipment will be added over the next 5 years.
The rapid development of the same time will bring certain problems, for example, because of the short equipment life, resulting in a large number of end-of-life electronic equipment processing problems. It is reported that lithium-ion batteries and supercapacitors have the advantages of high energy density, lightweight and can be integrated on flexible substrates. However, lithium-ion batteries are made from biodegradable toxic materials, and high energy consumption in the preparation process can cause damage to the environment.
Alternative energy-gathering technologies, such as solar cells, nano-generators and thermoelectric generators, also use a large number of non-renewable, refractory heavy metals and polymers.
As a result, the Choi team developed a paper battery has a clear advantage, in the paper battery scrap, bacteria will be ' swallowed ', to achieve degradation. In addition, Choi said, ' The advantage of using paper as a device substrate is that it can be stacked/folded at will, so that it can be connected in tandem or in parallel.
' The work of the Choi team was supported by the National Science Foundation (USD 300,000). As early as 2015, they used oxygen electrodes from their own respiration to spray nickel onto paper and to develop a battery that folds into square blocks (the size of a match box). The total cost of the battery is only 5 cents.
They acknowledge that paper batteries provide a tiny amount of electricity, but it is a great idea to be able to combine with bacteria to make batteries using these ubiquitous resources.
Recently, at the NO. 256 Annual meeting of the American Chemical Congress (August 19), Choi reported how the biological batteries were activated and how their shelf life improved. The principle of bacterial cells is that the biochemical energy stored in organic matter through the respiration of bacteria can be transformed into biological energy.
The conversion process involves a series of reactions that occur in biological molecules (electronic carriers). A bacterial-driven paper battery, developed by the Choi team, was placed on paper with a freeze-dried ' production of electrical bacteria '. The production of electrical bacteria can transfer electrons outside the cell and contact the external electrodes to provide power.
To activate the battery, they add water or saliva. The maximum power of paper battery can reach 4µw/cm2, current density can reach 26µa/cm2. Choi said the results were far higher than the paper-based microbial batteries. However, even so, dynamic performance is still very low, limiting its application.
In order to achieve commercial applications, the power/current density must be increased by at least 1000 times times. In fact, the Choi team is not the only research team that makes paper based batteries. In the 2017, researchers from Spain, Canada and the United States reported a nonmetal, biodegradable redox flow battery for a portable, one-time-use scenario. The batteries, which run for 100 minutes, are buried in the soil and treated with microbial degradation, similar to backyard composting.
The potential disadvantage of the battery, says Choi, is that the biodegradability requires favourable landfill treatment conditions.
The Choi team's paper batteries were degraded by bacterial phagocytosis without landfill, and Choi said their newest paper-Polymer composite bio-cells were easily degraded in the water.
Using bacteria-driven paper batteries, Choi says, can deliver energy to various places, even where there is no grid, to power light-emitting diodes and calculators. In addition, innovative engineering techniques can be used to control the diameter of the fibers in the paper, eliminate roughness, and control transparency, thus widening the application area.
The combination of paper with organic, inorganic and biological entities broadens the scope of engineering possibilities and makes paper a ' viable platform ' for the next generation of electronic products. At present, the storage life of paper batteries is 4 months. The Choi team is trying to improve the survival and performance of freeze-dried bacteria to prolong life.
They have also applied for patents and are looking for industry partners to promote commercialization. Office paper big Change Body! can be used to make environmentally-driven environmental protection | ' Paper battery '