Silent Sensors sponsors Green Piezo PhD student at Bath University
Silent Sensors has been working on generating power from piezoelectric materials in tyres for the past five years, working with a major tyre manufacturer.
There is no ideal material available – and looking forward with environmental challenges, a “friendly” material needs to be developed. In 2023, Silent Sensors decided to be part of that challenge and sponsor a PhD student with the University of Bath to make “green piezo” a reality. The lead supervisor for this project is Dr Hamideh Khanbareh with Dr James Roscow and Prof Matthew Jones as co-supervisors.
This project aims to create the first fully recyclable piezoelectric ceramic-polymer composite that can replace the existing components in sensors, actuators, and energy harvesters. This will allow the remanufacture of lead-based piezoelectric ceramics, which are the current industry standard, and will minimise its loss to the environment.
The Green Piezoelectric technology will provide a new approach to synthesising recyclable yet highly functional composite materials. The high tailorability and the improved piezoelectric response as well as high strength of the Green Piezoelectrics will allow for superior sensing and better energy harvesting devices. This will permit substitution of hard-to-recycle monolithic electro ceramics with easy-to-recycle and remanufacture composites of comparable performance, thereby minimising their environmental impact.
The Green Piezoelectrics will be able to be deconstructed to release the piezoelectric ceramic particles for reuse, bringing benefits in relation to the circular economy. The radical impact of this new sustainable materials design will be the reduction of e-waste, through component disassembly, materials recovery and remanufacture.
The Green Piezoelectrics approach will also presumably impact every other type of functional ceramic materials such as dielectric, conductive, and magnetic ceramics, opening new avenues for maximising value and minimising environmental impact through life from cradle to cradle as opposed to the conventional cradle to grave approach.
What is innovative in this project?
Piezoelectric materials that are at the heart of a wide range of medical, safety, transport and military applications are currently dominated by lead-based materials, such as lead zirconate titanate (PZT). Nowadays the existing electrical components end up in landfill and are left to biodegradation. The toxic truth is that this waste contains ∼1450 tonnes of lead per year causing significant health and environmental risks.1,2 Currently 800 million children around the globe have alarming lead levels.3 Recent studies have shown that the environmental impact of large-scale production of alternative lead-free ceramics would be worse than that of PZT.4,5 Hence, the elemental recovery and recycling is highly crucial to reduce waste and pollution.
This project will develop electroceramic materials that can be fully recovered and reused without compromising their functional properties. Currently electroceramics are not designed for ease of disassembly at end-of-life as ceramic grains are fused together during high temperature sintering processes. We will use a facile and scalable concept to achieve superb control over micro-structure formation via self-assembly of core/shell piezo ceramic platelets formed by adsorption of reversible nanoscale polymeric bridging between platelets. The organic phase itself will be based on Poly(lactic acid) (PLA), a sustainable aliphatic polyester that has recently been chemically recycled at Bath.
Such self-assembled microstructures are characterised by maximum amount of electro ceramic phase arranged in a highly ordered fashion. This will i) maintain the high functionality of the ceramic by minimising the polymer content, ii) makes it possible to induce highly structured particle arrangements based on the mode of sensing or energy harvesting to maximise application driven performance, and iii) enables extraction of the ceramic particles at the end of life by removing the polymeric bond between them.
Crucially, the Green Piezoelectrics will be able to be deconstructed (via reversible mild acid/alkali or oxidative/reductive environmentally benign chemistry) to release the constituent high-value ceramic particles for reuse, bringing wide-ranging benefits in relation to the circular economy within the electronics sector. This will permit substitution of hard-to-recycle monolithic electroceramics with easy-to-recycle and remanufacture composites of comparable performance, thereby minimising their environmental impact.
The aim of this project is to create green piezoelectric ceramic composites to effectively harvest mechanical energy in flexible systems such as car tyres. The high-strain environment of automotive tyres leads to deformations, allowing energy to be harvested using piezoelectric materials to power electronics such as Tyre Pressure Monitoring Systems (TPMS). This project will provide harvesting materials for an autonomous wireless sensor system with a reduced reliance on batteries, which will simplify sensor maintenance and management, and thereby improve safety and reduce waste associated with disposable batteries.
Piezoelectric materials that are at the heart of a wide range of medical, safety, transport and military applications are currently dominated by lead-based materials, such as lead zirconate titanate (PZT). Nowadays the existing electrical components end up in landfill and are left to biodegradation. The toxic truth is that this waste contains ∼1450 tonnes of lead per year causing significant health and environmental risks.1,2 Currently 800 million children around the globe have alarming lead levels.3 Recent studies have shown that the environmental impact of large-scale production of alternative lead-free ceramics would be worse than that of PZT.4,5 Hence, the elemental recovery and recycling is highly crucial to reduce waste and pollution.
This project will develop electroceramic materials that can be fully recovered and reused without compromising their functional properties. Currently electroceramics are not designed for ease of disassembly at end-of-life as ceramic grains are fused together during high temperature sintering processes. We will use a facile and scalable concept to achieve superb control over micro-structure formation via self-assembly of core/shell piezo ceramic platelets formed by adsorption of reversible nanoscale polymeric bridging between platelets. The organic phase itself will be based on Poly(lactic acid) (PLA), a sustainable aliphatic polyester that has recently been chemically recycled at Bath.
Such self-assembled microstructures are characterised by maximum amount of electro ceramic phase arranged in a highly ordered fashion. This will i) maintain the high functionality of the ceramic by minimising the polymer content, ii) makes it possible to induce highly structured particle arrangements based on the mode of sensing or energy harvesting to maximise application driven performance, and iii) enables extraction of the ceramic particles at the end of life by removing the polymeric bond between them.
Crucially, the Green Piezoelectrics will be able to be deconstructed (via reversible mild acid/alkali or oxidative/reductive environmentally benign chemistry) to release the constituent high-value ceramic particles for reuse, bringing wide-ranging benefits in relation to the circular economy within the electronics sector. This will permit substitution of hard-to-recycle monolithic electroceramics with easy-to-recycle and remanufacture composites of comparable performance, thereby minimising their environmental impact.
The aim of this project is to create green piezoelectric ceramic composites to effectively harvest mechanical energy in flexible systems such as car tyres. The high-strain environment of automotive tyres leads to deformations, allowing energy to be harvested using piezoelectric materials to power electronics such as Tyre Pressure Monitoring Systems (TPMS). This project will provide harvesting materials for an autonomous wireless sensor system with a reduced reliance on batteries, which will simplify sensor maintenance and management, and thereby improve safety and reduce waste associated with disposable batteries.
References
1. Pisarenko, G. G. et al. Requirements for the transfer of lead-free piezoceramics into application. Journal of the European Ceramic Society 18, 3713–3715 (2017).
2. Bell, A. J. & Deubzer, O. Lead-free piezoelectrics – The environmental and regulatory issues. MRS Bulletin 43, 581–587 (2018).
3. Rees, N. & Fuller, R. The Toxic Truth: Children’ s Exposure to Lead Pollution Undermines a Generation of Future Potential. 1–90 (2020).
4. Koruza, J., Webber, K. G., Wang, K., Bell, A. J. & Fr, T. Requirements for the transfer of lead-free piezoceramics into application. J Materiomics 4, (2018).
5. Ibn-Mohammed, T. et al. Life cycle assessment and environmental profile evaluation of lead-free piezoelectrics in comparison with lead zirconate titanate. Journal of the European Ceramic Society 38, 4922–4938 (2018).
6. Payne J, McKeown P, Mahon MF, Emanuelsson EAC, Jones MD. Mono-and dimeric zinc (II) complexes for PLA production and degradation into methyl lactate-a chemical recycling method. Polym Chem.11(13):2381–9 (2020). 25.