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Graphene is being used in many different forms and in many functional products, with the portfolio of graphene products on the market continuously increasing. A lot of interest has been shown in graphene’s use in batteries, and it has since become an area of intense research and development.
Advances with graphene batteries are being made at both an academic and commercial level, using graphene and graphene oxide materials. One of the latest developments to arise has come from Australian company Strategic Elements, which has developed a self-charging battery using graphene oxide-based inks. The company is a subsidiary of Australian Advanced Materials.
It has been predicted that the battery could self-charge itself within minutes by generating electricity from the humidity in the air or the skin's surface. Such capabilities could significantly impact the battery space. A total of one liter of battery ink could be used to create more than 2000 printable battery cells—showcasing the scale-up potential.
The project is being undertaken in conjunction with CSIRO and the University of New South Wales and aims to be developed using Strategic Elements’ Nanocube Memory Ink technology.
The Nanocube Memory Ink is a transparent liquid ink that contains billions of nanometer-sized cube-shaped particles. It is see-through and is a full-printable technology when it is printed on to a glass or plastic substrate. The teams have used the Nanocube Memory Ink as the base formulation and added in graphene oxide to create the graphene oxide battery ink.
The Current Stage of Development
Work has already been undertaken on these batteries, and some preliminary results have been found, but there is still more work to do. The graphene oxide battery inks trialed so far have been dispersed in water and coated on glass substrates. More than 100 battery cells have been fabricated up to now.
The team also has preliminary results in the properties of the batteries. The batteries developed to date have been able to self-charge using water-vapor in the air in just under three minutes. In terms of size, the batteries are thinner than a human hair and are about 10-20 microns in thickness, with other dimensions coming in at around 1 cm (but there is the potential to make them smaller).
The batteries generate more than 0.7 V of power in a cell, but the hope is that it will increase to over 3.7 V within the next 12 weeks. The team has also laid out some plans for the coming weeks. It intends to optimize the ink formulation, scale up the battery ink batch size to at least one litre, and successfully connect multiple battery cells to achieve the higher power levels.
Batteries for the IoT
While it is still a work-in-progress technology, one of the key application areas that could see the use of such batteries is the Internet of Things (IoT), as these batteries do not require any external (wired) or manual charging. This means they can be used remotely.
There is a lot of potential in this space to push forward the use of graphene-batteries in more real-world scenarios as the global battery market for the IoT was worth US$8.7 billion in 2009 and is forecast to be worth US$15.9 billion by 2025.
The self-charging battery space is becoming a hot area for the IoT. Most of the applications do not have access to an external power source, such as medical sensors and wearable healthcare devices, environmental monitoring sensors, smart meters, and home automation products, to name a few. Therefore, the market is there, and the graphene battery now being developed could make it more suitable than other options.
For example, there is a growing need for thin and flexible wearable electronics, particularly in the healthcare space. Graphene and graphene oxide technologies are inherently thin thanks to the single to few atomic layers of graphene sheets used to create them. One of the issues over the years within this sector has been finding efficient and flexible batteries that can power themselves.
A printable graphene ink battery has several significant advantages over other battery types (particularly Li-ion batteries) when it comes to IoT applications. Aside from the ability to self-charge, the batteries will be flexible, non-flammable, extremely thin and light, and considered environmentally friendly.
Therefore, while Li-ion may be the current gold standard in a general setting, graphene batteries could become the gold standard for IoT applications (and other applications requiring a flexible battery) in years to come due to their inherent flexibility potential for self-charging. Their required power levels tend not to be as high in smaller IoT devices than larger electronic devices.
Strategic Elements’ is currently looking to produce such an option that has the potential for scaling. Many flexible graphene batteries have been made over the years, but not all of them are scalable. Therefore, there is an opportunity here to not only develop flexible graphene-ink batteries that are suitable for IoT applications, but there is also the potential to help build the flexible battery market by making scalable and commercially feasible graphene-ink batteries.
Nanotech Energy: Graphene-Based Batteries for Revolutionary Energy Storage
References and Further Reading
Strategic Elements. Nanocubes [Online] Available at: https://www.strategicelements.com.au/projects/nanocubes/?portfolioCats=15
Cummins, J. (2020) Strategic Elements escalates development of self-charging battery technology. [Online] Proactive Investors. Available at: https://www.proactiveinvestors.com.au/companies/news/932767/strategic-elements-escalates-development-of-self-charging-battery-technology-932767.html
TMC. (2020) SOR Developing Flexible Self-Charging Battery. [Online] Available at: https://www.tmcnet.com/usubmit/-sor-developing-flexible-self-charging-battery-/2020/10/26/9245061.htm
Peleg, R. (2020) New self-charging graphene-oxide ink battery is under development. [Online] Graphene Info. Available at: https://www.graphene-info.com/new-self-charging-graphene-oxide-ink-battery-under-development