New highly efficient material turns motion into power – without toxic lead

Embargoed copy of the research paper available on request

Scientists have developed a new material that converts motion into electricity (piezoelectricity) with greater efficiency and without using toxic lead - paving the way for a new generation of devices that we use in everyday life.

Publishing their discovery in Journal of the American Chemical Society today (26 Nov) researchers from the University of Birmingham, University of Oxford, and University of Bristol describe a material that is both durable and sensitive to movement - opening possibilities for a wide range of innovative devices such as sensors, wearable electronics, and self-powered devices.​

Based on bismuth iodide, an inorganic salt with low toxicity, the new soft, hybrid material rivals the performance of traditional lead-based ceramics but with lower toxicity and easier processing. It contains no lead compared to existing high-performance alternatives such as PZT (lead zirconate titanate), which is 60% lead, and can be produced at room temperature rather than 1000°C.

Piezoelectric materials generate electric charge when pressed or bent and can also deform when an electric field is applied. They are essential to technologies ranging from precision actuators – used in products like camera autofocus and inkjet printer pumps – to energy-harvesting sensors built into wearable technology like fitness trackers, smart clothing, and car airbag systems.

Lead author Dr Esther Hung, from the University of Oxford’s Department of Physics who led the research, said: “By fine-tuning the interactions between the organic and inorganic components, we were able to create a delicate structural instability that breaks symmetry in just the right way.

“This interplay between order and disorder is what gives the material its exceptional piezoelectric response. It’s a different approach to piezoelectricity than in traditional materials such as lead zirconate titanate (PZT), and that’s what’s led to these big improvements.”

The global piezoelectric materials market is worth over $35 billion and continues to grow rapidly - driven by demand in automotive, healthcare, robotics, and consumer electronics, where devices that convert motion into electricity or precise movement are essential.

Researchers at the University of Birmingham used single-crystal X-ray diffraction and solid-state nuclear magnetic resonance (NMR) to understand the material’s behaviour. They found that the way that organic and inorganic parts stick together through halogen bonding can be used to change when and how the material changes its structure, as well as improving piezoelectric performance. This understanding could also be useful for enhancing piezoelectric performance in other materials that combine organic and inorganic elements.

Dr Benjamin Gallant from the University of Birmingham, who led the NMR study, said: “As an early career researcher, it’s exciting to participate in research with the power to transform our society - almost every device we use in our daily lives contains piezoelectrics.”

The research was jointly supervised by Professor Henry Snaith (Oxford), Dr Harry Sansom (Bristol), and Dr Dominik Kubicki (Birmingham), bringing together expertise in new materials, crystal design, and atomic-level structure characterisation.

Dr Dominik Kubicki from the University of Birmingham said: “With performance comparable to commercial piezoelectrics but made from non-toxic bismuth, this discovery is a new pathway toward environmentally responsible technologies that can power sensors, medical implants, and flexible electronics of the future.”

ENDS

For more information, please contact the Press Office at the University of Birmingham on pressoffice@contacts.bham.ac.uk or +44 (0)121 414 2772

IMAGE CAPTIONS – please credit University of Birmingham/University of Oxford:

• From left, Dr Benjamin M. Gallant, Dr Esther Y.H. Hung and Dr Harry C. Sansom conducting single crystal X-ray diffraction measurements on the new piezoelectric material using synchrotron radiation at the Diamond Light Source, Oxfordshire, UK.
•  From left, Dr Benjamin M. Gallant, Dr Dominik J. Kubicki and Dr Shrestha Banerjee in front of a solid-state NMR instrument in the Molecular Sciences Building at the University of Birmingham.
• A crystal of the newly discovered piezoelectric material viewed under a microscope.

Notes to editor:

• The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 8,000 international students from over 150 countries.
• 'Tailoring a lead-free organic–inorganic halobismuthate for large piezoelectric effect’ - Esther Y.H. Hung, Benjamin M. Gallant, Robert Harniman, Jakob Möbs, Santanu Saha, Khaled Kaja, Charles Godfrey, Shrestha Banerjee, Nikolaos Famakidis, Harish Bhaskaran, Marina R. Filip, Paolo Radaelli, Nakita K. Noel, Dominik J. Kubicki, Harry C. Sansom, and Henry J. Snaith is published in the Journal of the American Chemical Society. https://doi.org/10.1021/jacs.5c15484

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