Strategic Elements Ltd (ASX:SOR) has achieved a key milestone with its moisture-based battery technology producing more than a milliamp of electrical current from humidity in the air.
Its prototype battery Ink cells produced 100mAh (milliamp hours) of electric charge over three days.
The milestone of milliamp-range current output is a considerable achievement as it increases the potential array of applications that could be powered by the technology.
Further improvement in performance is expected over the next few months as the prototype ink becomes increasingly optimised for use in screen printing equipment.
Successful milliamp development
The company has successfully fabricated a 6 x 6-centimetre prototype achieving over 1mA of current output under load over a 35-hour testing period.
Battery ink cells could either be used to directly power a device such as the above or complement a battery to extend device life.
These different use cases provide alternative commercialisation and partnering options for the company.
Increased reliability
Strategic Elements has also successfully re-designed the battery cell architecture using larger battery cells whilst reducing the number of cells required.
This has resulted in a very simple battery structure with fewer components and more reliability allowing for simpler manufacturing.
The company’s objective was to fabricate prototype battery ink cells targeted towards health-related skin patches, producing one milliamp of electrical current.
Commercially available products such as glucose monitoring patches are about 6 x 6-centimetres in size and use low-cost batteries with a capacity of 220 mAh.
Battery life is about three days, which is an issue for users. It also prevents manufacturers from integrating additional functions into the devices as this would drain the battery even faster.
Further development
The battery ink is being developed by integrating significant existing ink formulation and printed electronics IP from the company’s nanocube memory ink technology.
Development has progressed from low voltages to 0.8V per cell, small scale ink to 1L batches and from microamp to milliamp range of electric current output.
Fabrication has moved from lab methods to small area screen printing of the battery ink, which has set the foundation for the next stage of advancement in the technology.
Initial focus on skin patch segment
The initial focus remains on the skin patch segment of the electronics sector as it has a very large global market, as most current requirements are lower (500 µA – 5 mA) with less capacity ( 220mAh) and duration needs are shorter (1- 7 days).
Other benefits of the battery ink technology such as the thin, lightweight, flexible, environmentally friendly, non-flammable nature of the battery cells make it an ideal candidate for the electronic skin patch segment.
Market for skin patches
The electronic skin patch sector is the initial commercial focus for the technology as it produced US$10 billion in revenue in 2019 and is forecast by IDTechEx to grow to nearly US$40 billion by 2030.
It also has lower requirements, such as duration, current and voltage, than other electronics sectors.
Next steps
In the short term, development will remain focused on the larger battery ink cells and simpler architecture specifically targeted towards the electronic skin patch sector.
SOR’s objective is to increase current output to over 5mA and produce at least 220 mAh of electric charge from a single battery ink device in the fourth quarter of 2021.
The battery ink technology is still in early development and the fundamental upper limits of aspects such as maximum power output, duration, energy density remain unknown.
Multiple avenues to potentially increase performance significantly have been identified by the team at UNSW.
Secondary work has also commenced to various aspects such as ink formulation, battery cell size and architecture relevant to applications requiring higher performance than electronic skin patches.
The company will communicate these developments as appropriate.