Cross-Institutional Research Exchange Programme

Four postdoctoral researchers took part in cross-institutional research exchanges during 2018/2019, as part of a wider energy storage research programme.

The exchanges were funded by the Multi-scale Analysis for Facilities for Energy Storage (MANIFEST) project, an EPSRC supported research initiative. Using state-of-the-art facilities funded through the Eight Great Technologies Capital Grants Call, the project is focussed on improving the performance and reducing the costs of energy storage technologies, and to better understand how energy storage could be deployed in energy systems.

The premise of the researcher exchanges was to support work on common research challenges between energy storage technologies and encourage collaborative working across institutions. The exchanges ensured that early career researchers from the energy storage field will grew their networks and gained valuable collaborative experience with other leading research groups in the UK.

Competitive applications were invited from eligible postdoctoral researchers, employed by any of the fourteen collaborating institutions on the MANIFEST project.

Dr Jonathan Radcliffe, Reader in Energy Systems and Policy Analysis and PI for MANIFEST, said, “The researcher exchange programme provided a valuable opportunity to develop new collaborations for researchers in the early stages of their academic careers. In parallel, the successful applicants addressed some of the most interesting challenges surrounding energy storage technologies and their integration into the energy system. Through the researcher exchange programme, we are able to deliver impact, not only by addressing key research questions using multi-disciplinary expertise but also through developing early stage researchers for the future.” 

Four successful applicants were awarded funding for their research, consumables, travel and subsistence costs. Each applicant has summarised their exchange, all of which can be found below. We would like to thank all of the researchers that took part in the exchange, whom are listed below:

Dr Xuekun Lu

Dr Xuekun LuDr Lu is a researcher at University College London and completed his exchange with Professor Yulong Ding’s group at the University of Birmingham. His project focused on multi-scale 3D characterisation, correlative imaging and modelling of lithium-ion batteries.
Summary of the activities and impact of the research exchange that took place during 2018-2019. 

Describe the area of focus for your researcher exchange? 

The area of focus in this exchange programme is understanding the interplay between the electrochemical performance and microstructure in energy storage materials via multi-length scale image-based modelling technique, which will provide more insights into the design of next-generation battery electrode towards the improved energy/power performance and phase change materials (PCM) for high efficient energy storage and thermal management of the battery. 
In a bid to reverse the global warming and cutdown fossil fuel consumption, substantial effort has been made to facilitate the revolution of electric vehicles, the market penetration of which is highly dependent on the accessible driving range, cost and safety. These are closely linked to the microstructure of the electrodes. Unravelling the fundamental science and underlying physical processes of the interplay between local/global performance and microstructural parameters have a significant impact on advanced electrode design, engineering and manufacturing. Moreover, the fast development of PCM in the last years provide a new alternative in battery thermal management system due to its high energy efficiency, low cost and sustainability.  
Thus, this research exchange programme will be an important part of the Faraday Battery Challenge, aiming to use correlative imaging, advanced material characterisation and 3D image-based modelling to understand the fundamental science and predict performance of energy storage materials. The knowledge of the mass transport and electrochemical performance will be translated to improvements of microstructure design and optimisation at the cell level and eventually the system level. 

How did the work you carried out during your exchange fit the MANIFEST research programme? 

During this visit, we conducted large amount of electrode preparation, assembling and electrochemical test to measure the fundamental but critical metrics used for battery modelling, such as OCV, solid-state diffusivity and charge transfer resistance. It is of great importance to build the battery model based on the kinetic parameters directly measured from the as-prepared material instead of references to improve the reliability of the prediction of electrochemical state variables such as state-of-lithiation, heterogeneous charge transfer density etc. This is critical in unravelling the dependence of global material performance on the local microstructure and is highly consistent with Task 2.1 and 2.2 in WP2 of MANIFEST programme. 
 
I also discussed with Dr. Zhiwei Ge and Mr. Yanqi Zhao in Prof. Ding’s group regarding the data analysis of the thermal chemical material and PCM obtained from the X-ray computed tomography and develop image-based model to track the microstructural evolution after thermal cycles, proposing new geometry for the application of PCM embedded foam copper to the battery thermal management. This is well aligned with another target of the MANIFEST research programme - to investigate an effective way to integrate the energy storage device into the energy system.  
We also discussed the possibility to leverage the multi-scale imaging suite located in Electrochemical Innovation Lab in UCL to aid the materials modelling from sub-micron to centimetre length scale to examine the scalability of the current microstructure design. 

How did you benefit from taking part in the MANIFEST exchange programme? 

As a modeller, personally I learnt a great number of experimental skills, from battery fabrication ans Swagelok cell assembling, to the operation of three electrodes electrochemical test, Potentiostatic Intermittent Titration Test (PITT) and Galvanostatic Intermittent Titration Test (GITT) and Electrochemical Impedance Spectroscopy (EIS), by which I can find out the essential modelling parameters that cannot be extracted from X-ray tomography data. These experiments provide me with new insights into linking the battery modelling with the experiment and what in turn can inform the experiment design for the examination and improved understanding of the battery degradation mechanism. 
I also have had a better understanding of a wide range of different energy storage materials, their principles and applications, which substantially broadens my vision about the energy conversion and also, enlightened me how I can apply my expertise in 3D microstructural characterisation and modelling to help the material design and optimisation in more comprehensive instances.  
In a long term, I have made contacts with the talented researchers in Prof. Ding and Prof. Kendrick’s group and understood their projects. This undoubtedly will create potential collaboration possibilities and further academic activities between University of Birmingham and University College London.

What were the main outputs of the researcher exchange? 

The first outcome of this exchange programme is that a 3D microstructure-resolved physics-based battery model for material design and performance prediction is developed, based on the obtained kinetic parameter from the lab. With the experiment data, the faithfulness of the original model is considerably enhanced. The heterogenous intercalation in Li-ion battery as a function of different discharge C-rate, the electrolyte concentration distribution and the Li-ion flux spatial distribution thus can be quantified and visualised (see figure). This highlights the importance of microstructure control in manufacturing. For example, it is found that the particle size, shape, pore size and porosity in the vicinity of the separator are dominant in determining the rate capability of the battery charge and discharge. A comparison of different perspective microstructure for next-generation battery electrode will also be undertaken. This will be discussed extensively in the paper to be published.   

What plans do you have for further collaborations with your host institution? 

There will be very profound and planned collaborations in the near future. For instance, the effect of electrode calendaring and the resultant porosity, electrode thickness on the battery performance will be examined systematically by linking X-ray CT 3D microstructure and image-based modelling to the electrochemical test to verify the state-of-the-art processing parameters so as to rationalise the manufacturing. Battery degradation as a function of cycle times and fast-charge/discharge will also be investigated by the performance and microstructure correlation. 
Comprehensive microstructure characterisation on PCM embedded copper foams of distinct feature size will be undertaken, followed by thermal simulation based on X-ray tomography data to verify the efficacy of different designs and the application of PCM on battery thermal control. Microstructural evolution of thermal chemical energy storage material from the fresh to reacted states will be tracked, quantified and modelled to highlight the relationship between the material thermal resistance and cycle time.

Dr Evan Wenbo Zhao

Dr Evan Wenbo ZhaoDr Zhao is a researcher at the University of Cambridge and he carried out his exchange at the University of Manchester with Professor David Collison’s group. His project focused on developing in situ electron spin resistance characterisation techniques for organic based redox flow batteries. 

Summary of the activities and impact of the research exchange that took place during 2018-2019. 

Describe the area of focus for your researcher exchange?  

Electron Paramagnetic Resonance (EPR) spectroscopy is powerful tool to study radical species by detecting the spins of the unpaired electrons. The in situ Nuclear Magnetic Resonance (NMR) experiments of organic-based redox flow batteries performed in Prof. Grey’s laboratory have revealed the formation and consumption of anthraquinone radical anions and charge transfer processes between the radical anions and the molecules. To directly detect the radical species, probe the electron spin density and charge transfer, we developed and performed in situ EPR experiments at Prof. Collison’s laboratory. Combining the in situ NMR and EPR techniques, unprecedented detection of the molecular transformation and charge transfer in a flow battery was achieved and will be used to guide the rational design of long-lasting and high-performance organic flow batteries. 

How did the work you carried out during your exchange fit the MANIFEST research programme?  

The work fits the work package 1 of the MANIFEST research programme, i.e. characterisation and processing of electrochemical and thermal materials for grid scale storage applications. Redox flow battery (RFB) technology is one of the most promising for grid scale energy storage because of its inherently decoupled energy storage and power generation. Metal-based inorganic RFB currently dominates the flow battery market. However, due to the high cost and potential environmental hazards, metal-based RFB systems face challenges for deep market penetrations. Organic-based RFBs which make use of inexpensive and sustainable redox-active organic materials could resolve these issues. Despite the promising aspects and tremendous interest from academia and industry, organic-based RFBs have lower energy density and shorter lifetime, compared to the more mature vanadium-based RFBs. The molecular origin of the electrolyte instability is not well understood, and insight is required to motivate further molecular engineering strategies to improve stability. We developed an in situ EPR characterisation technique to study this type of flow battery, filling the gap between molecular design and electrochemical testing with real-time information at the molecular level. 

How did you benefit from taking part in the MANIFEST exchange programme? 

 By attending the EPR workshops and performing the EPR experiments with Mr. Adam Brookfield and Prof. Collison during the exchange programme, I improved my understandings of EPR fundamentals and enriched practical experience of EPR techniques. I started to develop a unique skill set of coupling flow chemistry with EPR spectroscopy. As an NMR spectroscopist by training, developing skills in EPR spectroscopy is particularly beneficial because of the fundamental similarity in terms of the spin dynamics and yet different technical requirements of these two techniques. By coupling NMR and EPR techniques, I gained a deep insight of the chemistry and electron-nuclei spin interactions happening inside a flow battery. Moreover, establishing connections with the top-notch EPR scientists in UK will be beneficial to my academic career in the long term.

What were the main outputs of the researcher exchange? 

We successfully developed an in situ EPR technique to study an operating flow battery. The EPR measurements were performed for three quinone-based flow batteries. We detected radical formation during charging and discharging cycles of a full flow battery in operando. We studied the effect of electrolyte concentration on the electron spin-spin interaction by varying the concentration.     

What plans do you have for further collaborations with your host institution?

Following up the experiments that were performed during the exchange programme, we will further establish a calibration method to quantify the radical concentration accurately and correlate it to the state of charge of the flow battery. We will simulate acquired EPR spectra, in order to the map the electron spin density distribution on the radical molecule.  After the development of the in situ EPR technique at Prof. Collison’s laboratory, a sustained collaboration between the Researcher’s and the Host’s group is readily envisaged. Prof. Grey’ group is designing and synthesizing new organic electrolytes for flow battery applications. The in situ EPR technique developed during the exchange programme will be used as a routine characterisation for the new electrolytes.  

Dr Qingweig Zhu

Dr Qingweig ZhuDr Zhu is based at the University of Manchester and he completed his exchange at the University of Sheffield with Professor Dave Stone’s group. His project focused on characterisation and control strategies of energy storage systems, as well as hardware-in-the-loop research techniques for smart grid research.

Summary of the activities and impact of the research exchange that took place during 2018-2019. 

Describe the area of focus for your researcher exchange?   

In the programme I have visited three MANIFEST Energy Storage System (ESS) pilot assets. These include a 90kW super capacitor system in Newcastle University, a 2MW commercial battery system in Willenhall (owned by the University of Sheffield), and a 15kW battery prototype ESS in the University of Oxford. The major focus of my work was to investigate the options for Ethernet communications and identify practical solutions to link these distributed ESS plants to the Manchester real time digital simulator (RTDS) system. The goal is to establish an ESS-network including extended hardware-in-the-loop system for further research on the coordinated operation of distributed ESS for frequency response services. To this end, I learned the details of the electrical architecture and more importantly the communication interface of these three ESSs during my visits. I discussed with the host research staff and supervisors and identified feasible solutions for each asset, which enables a fast data transmission and high security.     

How did the work you carried out during your exchange fit the MANIFEST research programme?  

WP3 of MANIFEST project is concerned with the grid Integration of BESS. The main objectives of WP3 are to examine the control and performance of storage assets at the equipment level and also on the wider grid scale, to blend the use of physical pilot plants with high performance simulation using the WP2 models, real-time data links and hardwarein-the-loop techniques. Particularly, pilot plant operation and a comparison of the performance and control strategy among the MANIFEST systems are the main jobs of task 3.1. My exchange work facilitated the comparative study (Manchester and Newcastle) of the ESS response time and the comparative study (Manchester and Sheffield) of the ESS roundtrip efficiency, which is a perfect fit to task 3.1. Task 3.3 is focused on the grid-wide control and coordination of ESS via hardware-in-the-loop, which allows real-time simulation of the linked ESS systems within a virtual power network. In the exchange, my work investigating Ethernet solutions and linking these distributed ESSs of the host institutes to Manchester RTDS, is directly aimed at task 3.3 and will allow the completion of this extended grid-widescale, hardware-in-the-loop platform, which is the basis for the following WP3 research topics, i.e. coordinated operation of distributed ESS for frequency response services, controlling transient behaviour of the system and potential interactions between the storage devices, understanding the behaviour of distributed generation during fault conditions.   

How did you benefit from taking part in the MANIFEST exchange programme?  

I’m really happy and grateful to take this researcher exchange opportunity to visit our MANIFEST partner institutes. Firstly, it was a great learning experience to me. I saw and learned about a wide range of fast response ESSs (battery and supercapacitor) of different battery types, different scales of energy/power capacity, and different electrical architectures. I learned about the control, monitoring and operation of these systems. Through the exchange work I also gained knowledge of the Ethernet communication techniques and improved my skill of Python coding for advanced dSPACE applications. In addition, getting to know and discussing with the researchers and supervisors at the host institutes during this exchange was a great experience for broadening my academic network and improving my communication skills.   

What were the main outputs of the researcher exchange?  

The main output from my researcher exchange is a practical plan for linking four MANIFEST ESS pilot plants, including Manchester, Newcastle, Sheffield and Oxford, with the RTDS simulator in Manchester, to establish an extended hardware-in-the-loop research platform. RTDS enables simulating extreme network scenarios that would be impossible to test in the real electricity grid, and could also emulate the role of an ESS aggregator. The established link among these MANIFEST pilot plants also enables coordinated system operation and tests for the MANIFEST research theme of frequency response services. The technical approaches to establish this ESS network were identified and preliminary progress has been made. So far, the link between the Manchester system and the Willenhall system has been established and remote control tests have been successfully conducted.  

Another output from the exchange programme is an exchange of the latest knowledge on characteristics and operation experiences of each side. Also, system characterisation procedures for battery ESS have been developed and shared among the involved MANIFEST partners. For example, an ESS response time characterisation document has been shared with Newcastle, tests have been carried out and comparative results between the Newcastle system and the Manchester system obtained; a round trip efficiency characterisation document has been shared with Sheffield, and comparative results between the Sheffield system and the Manchester system have been obtained. It is anticipated that this work will lead to joint publications.     

What plans do you have for further collaborations with your host institution?  

Immediate collaborations with Newcastle and Oxford to establish the Ethernet link with them will be carried on. A further collaboration among these MANIFEST partner institutes will involve integrating the Sheffield system into a substation grid model, and the Newcastle system and Oxford system into an urban LV grid model via our RTDS simulator, which would emulate an ESS aggregator. Then collaborative research areas will be developed like, coordinated control of distributed and hybrid ESS networks to optimize and verify control strategies, coordinated operation of distributed assets for providing enhanced frequency response (EFR) services, the impact of extreme and abnormal grid network conditions on grid-linked battery ESSs. Also, comparing the system scale round-trip efficiency of the battery systems with the Newcastle supercapacitor system would be another interesting area to investigate. 

Dr Chunping Xie

Dr Chunping XieDr Xie is based at the University of Birmingham and she completed her exchange at Newcastle University with Dr Haris Patsios’ group. Her project focused on carrying out an economic feasibility analysis for a hybridised energy storage system.

Summary of the activities and impact of the research exchange that took place during 2018-2019. 

Describe the area of focus for your researcher exchange?  

This proposed research focuses on large Solar PV plants (50-100MW) and the economic feasibility to be coupled with energy storage systems. In the UK, it is compulsory for all generators with a capacity of 50MW or more to provide Mandatory Frequency Response (MFR), including renewable generating units. When a PV plant is required to support the grid by providing MFR, the generator must be ready to supply Primary Responses (within 10 seconds up to 20 seconds) and Secondary Responses (after 30 seconds up to 30 minutes) or to reduce its output power for High-Frequency Events within 10 seconds. That means Solar PV plants may have to run at a derating mode to respond to the grid’s frequency events, which will reduce the economic effectiveness. As a result, this study proposes a PV coupled with Liquid Air Energy Storage (LAES) and Li-ion Battery (LiB) hybridised energy storage system, which enables the PV always running at its maximum capacity as the required MFR is provided by LiB. In the meanwhile, the additional energy storage unit, LAES, is used for bringing in extra revenue streams by arbitraging in the energy markets and providing balancing services to the grid in the ancillary service markets. Main contributions of this study include: 1) analyse whether it is economic feasible for adding a hybrid energy storage system to an existing large solar PV plant; 2) determine the optimal size for the hybrid energy storage system; 3) discuss the market opportunity for energy storage.  

How did the work you carried out during your exchange fit the MANIFEST research programme? 

For the MANIFEST project, one of the three key challenges is identified as: Energy storage technologies need to access value spread across markets though performance characteristics of a single device may limit their applications. To tackle this challenge and explore more revenue streams from ancillary markets, my proposal focus on a hybridised energy storage system based on the performance characteristics of each single device, to improve the economic feasibility for their applications.   

How did you benefit from taking part in the MANIFEST exchange programme?  

I had been to Newcastle University for attending the UK Energy Storage (UKES) 2018 Conference and was impressed by the research team at Newcastle University. Some research topics they have been engaged with are quite relevant to our work at the University of Birmingham. This exchange scheme was a great opportunity for communication between the two research teams and a chance to exchange idea in the area of energy storage. During the two weeks’ visiting at Newcastle University, I have received some valuable comments on my current research, and had helpful discussions and meetings with their research team, which have led to a detailed research framework for a joint paper.   

What were the main outputs of the researcher exchange?

The main output of the researcher exchange programme at the first stage is a joint paper entitled ‘Economic viability analysis on a PV-LAES-Battery hybrid energy storage system’, which we would like to submit to “Applied Energy”. I have submitted an abstract to the UK Energy Storage (UKES) 2019 Conference to be held at Newcastle University. I hope to present the joint paper on the conference and have a further discussion with the research team at Newcastle University based on comments and suggestions that we might have received. 

What plans do you have for further collaborations with your host institution?  

In the future collaborations, we could have more visits between the two research teams to strengthen our connection. Besides cooperating for the MANIFEST project and the joint paper, we could explore other opportunities to build a long-term link, such as submitting a grant application together.