Aerosol Deposition for Manufacturing and Developing Next Generation Dielectric Charge Storage Devices

Lead Research Organisation: University of Leeds
Department Name: Chemical and Process Engineering

Abstract

Robust dielectric charge storage devices offering reliable operation at high voltage and temperature are required for power electronics in renewable energy and for harsh environment electronics. A revolution has already taken place in wide band gap semiconductors, interconnects and high-temperature packaging, allowing operation at temperatures of 300C. Similar breakthroughs have yet to be made in dielectric charge storage technology: overcoming this barrier would advance electronics for power conditioning and conversion, energy storage, aerospace distributed control systems, deep well geothermal energy and defence applications. As well as thermal resilience, the new generation of Class II ceramic capacitors must operate reliably and safely at high voltages, especially important for power and energy storage applications.
The main goal of the project is to advance particle aerosol deposition (AD) as a product development and manufacturing tool for a new generation of capacitors based on novel alkaline earth meta-niobate dielectric ceramics. We will demonstrate single-chamber, multi-nozzle sequential deposition of dielectric and electrode materials, with sophisticated process control to fabricate multilayer structures comprising ceramic, metal and polymer materials. Benign capacitor failure modes will be investigated, exploiting the unique capabilities of AD for room-temperature fabrication and materials integration. The high ceramic densities and 10 nm scale pore sizes attainable by AD, together with an absence of thermally induced ceramic defects (because of our selection of dielectric material and avoidance of high temperature sintering) offers to realise performance levels unattainable from existing materials and manufacturing procedures.
Key components of the project are: continuous particle manufacture using cascade reactors for rapid compositional prototyping of ultrafine powders; jet milling for refinement of particle structure; computational fluid dynamics to support AD process development; experimental optimisation of AD parameters for the new dielectric materials; evaluation of the new capacitors in a power electronic converter. Understanding the interplay between manufacturing conditions and product properties is an essential element of this multidisciplinary project.
Aerosol deposition avoids a range of problems associated with high temperature processing that degrade dielectric ceramic performance. This future manufacturing route is relevant to single layer, mm scale thickness, and multilayer capacitors with > 1 um component layers. Deposition rates in excess of 10 um per min within a scalable manufacturing process offer a solution to the long-standing challenge of integrating a wide range of thermally dissimilar materials. The approach offers exciting possibilities for translatiion into an industrial manufacturing context, bringing advantages to the emergent field of wide band gap semiconductor based electronics.
The project will use the industry-focussed aerosol deposition manufacturing research facility at Manchester University, the first of its kind in the UK, funded by the Henry Royce Institute.

Planned Impact

New products targeted in this proposal will contribute to advances in high temperature electronics for the rapidly expanding power electronics and harsh environment electronics sectors. High voltage power conditioning, conversion, bypassing, filtering and signal coupling in the renewable energy sector and electric vehicle propulsion systems require new robust Class II ceramic materials that can operate safely at temperatures ~ 300 C and at electric fields of > 100 kV per mm. The new dielectric materials and capacitor manufacturing routes will also find applications in distributed engine control electronics in the aerospace industry, as well as deep-well drilling and defence sectors. Lack of 250C to +300C capacitors is a severe obstacle to designing electronic systems for applications where independent cooling is impractical or improved system reliability and efficiency would result from using high temperature components. Capacitor manufacturing companies will be able to implement product development programmes based on the results of the project. The new ceramic formulations could be integrated with minimal disruption to existing manufacturing routes. However the main goal remains to pioneer a new approach to capacitor manufacture and materials integration bringing longer term transformational benefits.
The project will utilise an innovative ceramic densification process, aerosol deposition. The outputs of the project will help establish aerosol deposition as a platform development and manufacturing technology, and generate other research proposals centred on the Henry Royce Institute. Here we specifically target dielectric charge storage end-use products, but the research to be demonstrated will stimulate further research interest and grant proposals by other UK Electroceramics research teams, for example in smart piezoelectric materials. The multiple aerosol nozzles and patterning masks to be demonstrated within the project are anticipated to provide a pathway for future 3D printing using aerosol deposition - a notoriously challenging platform for ceramics due to the present need for a high temperature sintering step. A successful outcome will open up new electronic materials integration possibilities, accommodating flexible substrates and multilayer architectures involving a benign failure mode for improved safety- to be pursued in the project. The new nanostructures and higher electrical breakdown strengths will have major impact on energy densities for storage applications, very relevant to the deployment of capacitors to complement large-scale battery systems.
Encouraging young people to study science and engineering will be part of the project's remit, implemented with the assistance of events such as: the Leeds Festival of Science; the annual public participation 'Be Curious' event; and by schools outreach and interactions with University Technical Colleges (including project display booths at Immersion Weeks). The University of Leeds Team for Public Engagement with Research will assist in wider public engagement to illustrate the importance of fundamental scientific research to the UK. Career opportunities of researchers will be improved by expanding skill-sets and working co-operatively in a multidisciplinary team. Transferrable skills will be improved by attending formal training courses at the Universities, and practicing communication skills within the project for example by presentations to industrialists at project meetings, annual steering meetings with Industrial Partners (including kick-off meeting) and the Workshop in Month 30. Industry have been involved in our research planning and will be engaged at all stages. The project will have academic impact in the areas of: particle science; mechanical engineering; chemical engineering; applied physics, manufacturing research and electronic engineering.

Publications

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