A team of scientists at UNSW Sydney has developed an eco-friendly, high-performance organic battery that could reshape the future of energy storage.
The breakthrough comes from a new rechargeable proton battery that stores energy using protons, the positively charged particles found in hydrogen atoms, rather than the widely used lithium.
This development holds promise for addressing some of the most pressing issues in current energy storage systems, including resource scarcity, environmental impact, safety, and cost.
The research, led by PhD candidate Sicheng Wu and Professor Chuan Zhao, was recently published in Angewandte Chemie.
The team created a battery that uses tetraamino-benzoquinone (TABQ), an organic material capable of storing protons.
“We have developed a novel, high-capacity small-molecule material for proton storage,” said Prof Zhao.
“Using this material, we successfully built an all-organic proton battery that is effective at both room temperature and sub-zero freezing temperatures.”
According to researchers, batteries, which convert chemical energy into electrical energy, typically rely on the movement of charge-carrying particles, or ions, between two electrodes: the anode and cathode.
Most household batteries today are lithium-ion, which transfer lithium ions between electrodes. These batteries power everything from mobile phones to electric vehicles but come with significant environmental and resource challenges.
Lithium, the primary material in these batteries, is a finite resource and difficult to recycle, requiring considerable energy and water to produce.
“Lithium-ion batteries are already becoming a dominant product in energy storage applications, but they have a lot of limitations,” said Wu.
“Lithium is a finite resource that is not evenly distributed on earth, so some countries may not have access to low cost lithium sources. Lithium batteries also have very big challenge regarding fast-charging applications, safety, and they have low efficiency in cold temperature.”
In response, proton batteries are emerging as an alternative, offering a potential solution with benefits such as faster charging, higher energy density, and the absence of harmful carbon emissions.
Protons, due to their small ionic size, can diffuse rapidly, making them ideal for energy storage applications.
However, current proton battery technologies face challenges, including the high cost of electrode materials and limited voltage range.
The UNSW team’s innovation involves modifying a compound called tetrachloro-benzoquinone (TCBQ) to improve its performance as an anode material.
By replacing chlorine groups with amino groups, the team developed TABQ, which significantly enhances the material’s proton storage capacity and lowers its redox potential range.
“If you just look at the TABQ material that we have designed, it’s not necessarily cheap to produce at the moment,” said Prof Zhao. “But because it’s made of abundant light elements, it will be easy and affordable to eventually scale up.”
The team’s initial tests of the proton battery prototype were promising. Paired with a TCBQ cathode, the battery exhibited a long cycle life—able to charge and discharge 3500 times—and maintained high capacity and excellent cold-weather performance.
The battery’s electrolyte, which is water-based rather than the flammable lithium salt used in lithium-ion batteries, adds to its safety and cost-effectiveness.
“The electrolyte in a lithium-ion battery is made of a flammable lithium salt, posing significant safety risks,” Prof. Zhao says.
“In our case, we have both electrodes made of organic molecules, and in between we have the water solution, making our prototype battery lightweight, safe and affordable.”
Looking ahead, proton batteries have the potential to play a crucial role in large-scale energy storage, especially for renewable energy systems.
The low cost, safety, and fast-charging capabilities of proton batteries make them an attractive option for grid-scale applications.
The research team is also exploring the broader implications of their discovery. By advancing proton transport mechanisms, they hope to enable hydrogen storage and transportation, a critical challenge for the hydrogen industry.
This research was conducted in collaboration with UNSW Engineering, ANSTO, and researchers from the UNSW School of Chemistry.
