The need
Sustainable use of energy is critical in the UK and worldwide, to cut greenhouse gas emissions and mitigate air pollution in urban areas. Energy storage is a major tool for enabling electric cars and renewable energy, and economic growth in these areas requires innovation through new materials.
Supercapacitors have a higher energy storage capacity than traditional electrolytic capacitors, but typically operate at a lower voltage. They are also able to charge and discharge energy very quickly, much faster than rechargeable batteries. Supercapacitors have the potential to help take the strain off the electricity grid as more renewable, but intermittent, energy sources are integrated into the power networks. They also benefit electric vehicles where they can provide acceleration performance enhancement and are expected to play an increasing role in superfast charging.
DZP Technologies (DZP) has been working to improve the performance of supercapacitors using commercially-scalable processes and novel, non-carbon 2D materials. In 2016, DZP approached NPL to increase their understanding of the material properties and associated performance improvements of novel supercapacitor electrodes incorporating these semiconducting 2D materials. In addition, DZP required quality control tools that were fast, non-destructive, affordable and could be operated without extensive experience, so the consistency of their product could be monitored in-house, rather than at a scientific laboratory with state-of-the-art equipment.
The solution
NPL has experience in investigating single layer flakes of molybdenum disulphide (MoS2) using a range of surface and nanoanalysis techniques and has a good understanding of the fundamental characterisation of non-carbon 2D materials. The request from DZP for support in development of supercapacitors led to both NPL and DZP securing a 12 month Innovate UK (IUK) project worth £151k.
As part of this work, DZP required two new inexpensive quality control (QC) processes that could be used in-house to characterise 2D materials and assess the subsequently-produced electrodes. NPL developed rapid non-destructive QC methods for characterising non-carbon 2D materials, MoS2 and tungsten disulphide (WS2). These methods enabled DZP to perform quick and inexpensive QC testing on the range of materials they would be producing and modifying.
As well as building on previous knowledge of the measurement of material properties, this project developed an electrochemical characterisation method for new electrodes. DZP worked closely with NPL researchers working on Surface Technology and Electrochemistry.
Importantly, the work in this IUK project revealed that non-carbon 2D materials, which can be produced by DZP in a commercially scalable way, can be used to improve the performance of supercapacitors.
The innovation of this IUK project was highlighted in the IUK report ‘Creating Value from Non-carbon 2D materials – beyond Graphene’ state of the art review, which noted how this was the only IUK project at the time addressing non-carbon-based 2D materials.
The impact
NPL and DZP developed rapid and inexpensive methods for characterising the size of MoS2 and WS2 flakes, as well as testing supercapacitor electrodes and understanding of how material properties impact electrode performance. These methods were able to characterise the 2D materials themselves, without the need for extensive experience in the techniques or expensive subcontract arrangements with external laboratories, which incur additional costs and associated lead times.
This work has enabled DZP to employ more staff and distribute new products into the international market. Such developments are helping to grow the UK economy and enabling the use of exciting materials in new application areas, such as electronics, sensors and energy storage.