Emerging paper-based electronics offer a simple, biodegradable, and cost-effective alternative to traditional devices, potentially slashing electronic waste. Researchers are advancing bio-batteries crafted from sustainable paper materials.
In many regions worldwide, basic technologies like batteries remain out of reach due to high costs. This challenge hits hardest for healthcare workers in remote areas, where diagnostic tools often fall short due to supply issues or prohibitive prices.
New, low-cost, portable, and efficient power solutions are essential. Enter paper batteries—a concept that's evolved significantly. Early versions lacked power and were hard to manufacture, but recent breakthroughs deliver both potency and simplicity.
At the University of Birmingham, Professors Seokheun “Sean” Choi from Electrical Engineering and Omowunmi Sadik from Chemistry have engineered a paper-and-biopolymer battery powered by bacteria, dubbed a "bio-battery."
“Paper has unique advantages as a material for biosensors," explains Choi. “It’s affordable, readily available, flexible, and has a large surface area. However, sophisticated sensors require a power source. Commercial batteries are too expensive and produce too much waste, and cannot be incorporated into paper structures. The best solution therefore remains a paper bio-battery.”
Researchers have created paper biosensors for detecting diseases and environmental pollutants, often via color changes—but accuracy suffers without power. Choi's team aimed for an affordable, bacteria-fueled paper battery seamlessly integrated with single-use sensors.
They printed ultrathin layers of metals and polymers onto paper, then applied freeze-dried exoelectrogens—bacteria that transfer electrons across their membranes. These electrons, produced during bacterial energy generation, contact the battery's electrodes.
Adding a drop of water activates the battery: bacteria revive in minutes, generating enough power to light an LED or run a calculator.
Biodegradability is key. Using PAA (poly(amic acid)) and PPDD (poly(pyromellitic dianhydride-p-phenylenediamine)) polymers, the battery dissolves in water within hours.
Oxygen diffusion through paper doesn't hinder performance much. Bacteria, anchored to paper fibers, shuttle electrons to the anode before oxygen interferes, yielding negligible power loss.
This single-use bio-battery lasts about 4 months and can be safely discarded. Choi is enhancing bacterial viability for longer life and better output.
“The generated power must further be increased by 1000 times before it can be put into common practical applications," notes Choi. Stacking units could achieve this.
