DESIGNING NANOPOROUS CARBONS AS ANODE MATERIALS FOR SODIUM ION BATTERIES

Lead Research Organisation: University of Surrey
Department Name: Chemical Engineering

Abstract

The UK faces the challenge to store energy from grid electricity generation (the current storage capacity is around just 3 GW, far short of the demand of around 20 GW). Greater capability (~10 GW) to store electricity will save the UK energy spend of up to £10 billion a year by 2050, and will provide flexibility for energy supply, as pointed out by the Rt Hon David Willetts MP in "Eight Great Technologies". It will also facilitate the increased use of intermittent renewable energies (such as wind, wave and tidal) on the grid to meet binding emission targets (for example, 80% CO2 reduction by 2050) and thus enable the faster transition to a low carbon society. This calls for low cost and sustainable energy storage technologies. Na ion batteries (NIBs) have recently attracted increasing interest worldwide, because of the natural abundance, wide availability and low cost of Na resources. They may be more economically viable than lithium-based batteries in the context of grid storage and can support the UK's and even the world-wide demand for electricity storage. The development of NIBs has, however, been very slow in the UK, compared to other competitors such as USA, Japan and China. This project aims to make advancements in NIBs with a focus on anode materials.

This project proposes the use of low cost and aboundant nanoporous carbons materials (particularly biomass derived carbon aerogels) as anode materials in NIBs. This proposal details a necessary step by providing a design tool for selection and optimisation of nanoporous carbons in this application. The hypothesis of the research is that computational models can be used to design desirable porous carbons for NIBs. The model development will be supported and validated by experimental activities including characterisation of real nanoporous carbons, assembly and testing of NIB cells.

Molecular models will be developed at two levels - a single pore model and a more complicated virtual porous carbon model. Hetreatoms (such as H, O, B, N, P, S) in the forms of doped atoms in the carbon lattices, and funcational groups, will be introduced, for the first time, to reflect the real atomic structures of porous carbons. Molecular simulations will be performed on the models to reveal Na ion intercalation mechanism in nanoporous carbons and the effects of pore sizes and presence of heteroatoms on the adsorption, diffusion and charge transfer processes. Desirable characteristics of porous carbons will be generated. These desirable charateristics will be used to guide the fabrication and optimisation of real nanoporous carbons.

This project is underpinned by a fully funded PhD studentship at Surrey, which will enable the prediction and the understanding from molecular simulations to be directly translated into real applications. Biomass derived nanoporous carbon aerogels, produced at Queen Mary University of London (UK), will be used to manufacture NIB cells at University of Surrey for electrochemical performance testing. Nanoporous carbons of other origin will be produced at CIC-Energigune (Spain) and used in battery cell manufacturing and testing. The project is also strongly supported by Johnson Matthey on materials characterization, battery testing, and advice on prototype opportunities.

This project is the natural result of the PI's expertise in molecular simulation, nanoporous carbon materials and electrode design for electrochemical devices. The framework of the proposed work will be underpinned by extensive energy materials characterisation expertise and infrastructure, as well as extensive expertise and facilities in battery manufacturing and testing at Surrey.

Planned Impact

This project aims to make advancement of Na-ion battery (NIB) technology. The project will lead multidisciplinary research to enable tuning of materials for improved performance and faster development of NIB technology.

The successful delivery of this project will lead to production of prototype NIB cells and future commercialisation of this technology, which provides a cheaper, cleaner, safer and sustainable energy storage solution. Moreover, molecular models of nanoporous carbons from this research could facilitate the design of carbons in supercapacitors, Li-air batteries and low-temperature fuel cells, with important impact on those industries.

Commercial beneficiaries of the research (wealth generation in 10 - 25 years) will be companies in the UK and worldwide in, or part of the supply chain for, NIB technology. More specifically, in the 5 - 15 year window, UK industry will directly benefit if the outcomes of the research lead to more developed and focussed academic-industry collaborations (Technology Strategy Board / Knowledge Transfer Partnerships). The potential IP that could be generated in the area of NIB technology for energy storage will yield opportunities for spin-out companies, providing employment opportunities and adding value to the UK economy.

Societal beneficiaries will include, for example:
- greater energy storage capacity in the UK and thus huge saving in energy bills for the public;
- large-scale employment of renewable energies (in the UK, particularly wind, wave and tidal energy) and thus the transition to a low carbon society;
- enhancement of UK's energy security and environmental sustainability.

In short-term (1-3 years), this project will provide highly skilled researchers who will have developed multidisciplinary skills and will have experienced a broad range of technological fields that are important for R&D programmes required for market innovation for NIB technology and beyond.

The PI will benefit several new collaborations with Johnson Matthey, Queen Mary University of London and CIC-Energigune (Spain), above established collaborations associated with her current research programmes. The UK-based and international partners are committed to supporting aspects of this project within their own research capacity. Further collaborations with leading groups and the development of multidisciplinary research projects will be fostered during this project.

Publications

10 25 50
 
Description Through the work funded on this award, we have gained a clearer understanding of Na ion storage mechanisms in nanoporous hard carbons, and the effects of different materials properties to enhance the performance of Na ion batteries. We find that pore size plays a significant role in sodium ion storage in nanoporous carbons. Particularly, high sodium ion storage density is obtained with pores smaller than 1 nm, at increased charges. This means that, to have high sodium ion storage capacity, we need to make carbon materials with pores dominantly below 1 nm. We also found that oxygen and nitrogen containing defects and functional groups commonly present in hard carbon materials can enhance the adsorption of Na ions. We also identified some oxygen containing defects to have the effect of increasing the metal ion migration barriers and thus could be detrimental to battery cycling and rate performance.

We also find that electrolyte solvent properties (including polarity, viscosity, molecular structure) play an important role in Na ion storage. We investigated the effects of different organic solvents and electrolyte salts, and found that organic solvents and salts with linear molecular structures are beneficial for enabling Na ions coming into the pores. Our study shows that it is important to include solvent molecules in the simulation, in order to accurately capture all the relevant interactions and thus the real battery system.

This project has enabled my group to start a new line of research in sodium ion batteries, by combined modelling and experimental efforts. Through the project, my group have developed methods of simulating battery systems containing the solid electrode material and the liquid electrolyte, by representing the atomic interactions explicitly. The methods are useful for investigating other battery systems, and have laid a step-stone towards developing new research. Our expertise in molecular modelling has attracted interest from industry partners such as Unilever and other research institutions such as Institute of Process Engineering (IPE), Chinese Academy of Sciences, to work with us. They have funded 3 PhD projects at University of Surrey into developing and designing health products using molecular modelling.

This project has enabled my group to develop collaborations with international research groups in Chiba University (Japan), Fujian Institute of Research on the Structure of Matter-Chinese Academy of Sciences (China), Loughborough University, Queen Mary University of London (UK), and Imperial College London, in materials design for batteries. These collaborations and links have led to joint publications and joint research grant funding (EP/R021554/1) to continue research in battery materials. I have enhanced visibility and have been invited to give a keynote talk at the 3rd International Conference on Energy Storage Materials (ICEnSM 2019) in Shenzhen (China) and give research seminars at various national and international institutions.

This project has enabled the training of an experienced postdoctoral researcher and diversified his research into a new field. This has led to the secure of a permanent research position for the researcher at Luxemburg Institute of Science and Technology. We have kept collaborations and will continue to collaborate in the future. The project has also enabled the training of a British PhD student on the fabrication and testing of sodium ion battery cells. A number of MEng final year students have been involved in the experimental study of sodium ion batteries. The PhD student, and the MEng students will be the work force for next generation electrochemical energy storage technologies and the driving force for innovation in new energy storage technologies.
Exploitation Route The findings from this project has been desseminated in peer-reviewed publications. The findings have also been disseminated at a number of international conferences including the 229th ECS (Electrochemical Society) meeting in USA, the 67th annual meeting of the International Society of Electrochemistry in the Netherlands, the 2nd international conferecen on Advanced Energy Materials in the UK, the UK-Korea Forum on Li and Na Batteries in the UK, and the 3rd International Conference on Energy Storage Materials (ICEnSM 2019).

The research methods developed in this project can be taken by other researchers to investigate battery systems. In fact, we have been transferring the methods and findings to colleagues in Chiba University and Chinese Academy of Sciences, to help them start new line of research.

The finding on the optimal pore sizes for sodium ion storage and the role of oxygen containing defects can be used by materials scientists (from universities or companies) to make high capacity carbon materials for sodium ion batteries. In fact, we have transferred the findings to our collaborators at Imperial College London for making desirable materials for sodium ion batteries.

At the 3rd International Conference on Energy Storage Materials (ICEnSM 2019), our work has received very positive comments from world-leading experts in Na ion batteries as "being very useful" to help explain experimental observations, and help design better hard carbon materials for Na ion batteries.
Sectors Chemicals,Education,Energy,Environment,Pharmaceuticals and Medical Biotechnology

URL https://www.surrey.ac.uk/people/qiong-cai
 
Description The findings on the desirable materials properties for hard carbons in energy storage batteries have been transferred to Lithium-sulphur batteries, which helped our collaborators at Loughborough University to design nanoporous carbon materials to achieve high energy storage capacity. The findings on the optimal pore sizes for sodium ion storage and the role of oxygen containing defects can be used by materials scientists to make high capacity carbon materials for sodium ion batteries. In fact, we have transferred the findings to our collaborators at Imperial College London for making desirable materials for sodium ion batteries. This project has enabled my group to start a new line of research in materials design by combining modelling and experimental research. Through the project, my group have developed molecular modelling methods for materials design. The methods are useful for investigating other battery systems, and have laid a step-stone towards developing new research. Our expertise in molecular modelling has attracted interest from industry partners such as Unilever and other research institutions such as Institute of Process Engineering (IPE), Chinese Academy of Sciences, to work with us. They have funded 3 PhD projects at University of Surrey into developing and designing health products using molecular modelling. The findings from this project have also been transfered to a PhD project funded at University of Surrey, on fabricating sodium ion based energy storage devices using nanoporous carbons of desirable pore sizes. We are in the process of making these devices better. If successful that will provide alternative energy storage technologies and will bring benefit to the UK economy.
First Year Of Impact 2017
Sector Energy,Environment
Impact Types Societal,Economic

 
Description Designing Electrodes for Na Ion Batteries via Structure Electrochemical Performance Correlations
Amount £1,200,000 (GBP)
Funding ID EP/P003354/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2018 
End 12/2020
 
Description Development of electrode materials for sodium ion batteries
Amount £60,000 (GBP)
Organisation University of Surrey 
Sector Academic/University
Country United Kingdom
Start 10/2015 
End 09/2018
 
Description EPSRC Impact Accelerate Account
Amount £40,000 (GBP)
Funding ID RN0301E 
Organisation University of Surrey 
Sector Academic/University
Country United Kingdom
Start 09/2016 
End 03/2017
 
Description DFT simulations of sodim ion interactions with organic solvents and carbons 
Organisation Chinese Academy of Sciences
Country China 
Sector Public 
PI Contribution My team perform density functional theory (DFT) simulations to understand the interactions of different sodium salts (e.g. NaPF6, NaClO3, NaFSI) with different organic solvents (e.g. PC, EC, EMC, DMC, etc), and derive their solvation energies. My team also perform DFT simulations to understand sodium ion interactions with carbon materials (i.e. single layer graphene, bilayer graphene) containing different surface functional groups (e.g. NH2, OH, COOH, etc.)
Collaborator Contribution My partners have many years experience in DFT simulations, particularly for systems that contain graphene and functional groups, and have charge transfer processes. They provide guidance in DFT simulations, and provide correct graphene structure and functional groups as input to DFT simulations. They also help review the results and provide expertise in understanding the results.
Impact This collaboration is multidisciplinary as it involves chemical engineering, chemistry and physics. The work is still on-going. We have a joint publication in Nanoscale, and is working on a second manuscript for publication.
Start Year 2017
 
Description Designing nanoporous carbons as cathode materials for lithium sulphur batteries 
Organisation Loughborough University
Department Department of Chemistry
Country United Kingdom 
Sector Academic/University 
PI Contribution My research team contributed out knowledge gained from the EPSRC funded project, for the design of nanoprous carbons as cathode materials for lithium sulphur batteries. We communicated to colleagues from Loughborough University that, for high Li storage, an ideal carbon should possess a hierarchical porous structure with the majority of pores around 1 nm and some pores in the range of 1-4 nm. We also shared our knowledge that morphology of carbon materials would affect the performance, and well connected spheres should give better performance than the randomly packed carbon particles with irregular shapes.
Collaborator Contribution Our partners at Loughborough University made the nanoporous carbons according to our advice, using phenol resin precursor, via CO2 activation. The as-made carbon materials are uniform spherical particles with diameter of 250 nm, and have a hierarchical porous structure with the majority of pores around 1 nm and some pores in the range of 1-4 nm. These nanoporous carbon spheres were impregnated with sulphur and used to fabricate the cathode of Li-S batteries, which showed excellent performance. The storage capacity reached 670 mAh/g after 500 cycles, which is among the highest reported Li-S battery performance.
Impact This is a multidisciplinary collaboration involving Chemistry and Chemical Engineering. This collaboration has led to a joint publication. The paper, entitled "A High-Volumetric-Capacity Cathode Based on Interconnected Close-Packed N-Doped Porous Carbon Nanospheres for Long-Life Lithium-Sulfur Batteries (DOI: 10.1002/aenm.201701082), was published in Advanced Energy Materials in 2017.
Start Year 2016
 
Description Developing advanced electrolytes for Li/Na ion batteries 
Organisation Chinese Academy of Sciences
Department Institute of Process Engineering
Country China 
Sector Academic/University 
PI Contribution My research team contribute to battery assembly and testing, as well as using advanced characterisation techniques to understand the behaviour of different electrolytes. We also develop novel electrolyte solutions that can reduce the degradation of Li/Na ion batteries.
Collaborator Contribution My partners at Institute of Process Engineering provide novel electrolyte solutions based on their expertise in ionic liquids.
Impact We expect to have outcomes by end of 2019.
Start Year 2018
 
Description Developing anode materials for high energy density Li/Na ion batteries 
Organisation Hubei University
Country China 
Sector Academic/University 
PI Contribution My research team use density functional theory to help understand the intercalation mechanisms of Li ions into high energy density materials, and support advanced characterisation of lithium ion battery anode materials.
Collaborator Contribution My partners at Hubei University synthesised novel materials to achieve high energy density Li ion batteries.These materials include Bi2MnO6 and Bi2WO6, and their hybrids with palm carbons.
Impact We have found the hybrid Bi2MnO6/carbon materials highly promising for achieving high energy density lithium ion batteries. We have one manuscript under preparation for publication.
Start Year 2018
 
Description Developing high energy density anode materials for Li/Na ion batteries 
Organisation Shanghai University
Country China 
Sector Academic/University 
PI Contribution My research assemble battery cells in our glovebox, based on the anode materials provided by my partners, and test the battery using our advanced potentiostats to understand the electrochemical performance. We also perform advanced characterisation of the materials using widely available techniques at Surrey including SEM, TEM, Raman, FTIR, XPS and XRD.
Collaborator Contribution My partners at Shanghai University synthesize composite silicon/carbon materials with tailored morphology.
Impact We expect to have some joint publications by end of 2019.
Start Year 2019
 
Description Grand Canonical Monte Carlo simulations of sodium ion storage in carbon nanopores with different electrolyte solutions 
Organisation Chiba University
Department Department of Immunology
Country Japan 
Sector Academic/University 
PI Contribution In this collaboration, we want to unravel the effect of pore size, type of electrolyte solvents, and surface charge on sodium ion storage in nanoporous carbons. We provide force fields parameters and simulation parameters such as pore sizes and surface charges to our collaboration partners who perform grand canonical simulations in relatively bigger pores (>2nm). We then compile these results together with those from our simulations in smaller pores (<2nm), and analyse the results to derive understandings of how the properties of different organic solvents affect the sodium ion storage in carbon nanopores.
Collaborator Contribution Our collaboration partners perform grand canonical simulations of sodium ion storage in in relatively bigger pores (>2nm), when different electrolyte solutions are present in the system. They derived radial distribution function profiles for different systems.
Impact This collaboration has led to generation of substantial results and understanding of how the properties of different organic solvents affect the sodium ion storage in carbon nanopores. Some of the first results are now published in Physical Chemistry Chemical Physics (DOI: 10.1039/c7cp04878e), entitled "The effect of different organic solvents on sodium ion storage in carbon nanopores. " We are currently working on another manuscript for publication.
Start Year 2016
 
Description Synthesis of nanoporous carbon materials for sodium ion batteries 
Organisation Queen Mary University of London
Department School of Engineering and Materials Science
Country United Kingdom 
Sector Academic/University 
PI Contribution My research team is utilising the nanoporous carbons developed at Queen Mary to fabricate sodium ion battery cells and test the performance. The aim is to systematically investigate the effects of porous structure (including pore size, surface area and pore chemistry) on sodium ion battery performance and identify the materials that give the best performance.
Collaborator Contribution My partner at Queen Mary has been making nanoporous carbons for us to be used in sodium ion battery cells.
Impact The research project is still on-going, and we hope to report the outcomes later. The collaboration is multidisciplinary, which involves chemical engineering, chemistry, physics and materials sciences. The partnership with Queen Mary has resulted in a joint proposal application in the same field: "ELECTRO_NIBs: Designing Electrodes for Na-Ion Batteries via Structure-Electrochemical Performance Correlations", which has been funded by EPSRC ISCF Wave 1 funding. The project started on 01 January 2018 and will finish on 31 December 2018. In this collaborative project, my team will contribute our modelling expertise to further investigate the Na ion storage mechanisms in Hard Carbons and hybrid carbon/Sn materials.
Start Year 2015
 
Description Understanding the role of porous electrodes in the performance of redox flow batteries 
Organisation Massachusetts Institute of Technology
Country United States 
Sector Academic/University 
PI Contribution My research team use our advanced 3D pore scale lattice Boltzmann model to simulate transport and multiphase flow, coupled with electrochemical reactions, within various porous electrodes for redox flow batteries. The model provide current and voltage profile across the electrode, and is able to separate the structure effect on concentration overpotential and activation overpotential. The simulations have helped to understand why different electrode materials (Freudenberg paper, SGL paper and carbon cloth) give different performance and provide a guideline as to what structure is desirable for achieving high performance in redox flow batteries.
Collaborator Contribution My partners at MIT test different electrode materials in their redox flow battery set up and provide experimental data to validate the model. Our partners at Imperial College London provide imaging data to input to the model, so that we could perform simulations directly on real porous electrodes, and compare the simulated performance with the experimental measurement, to validate the model.
Impact In this collaboration, we have improved our model to give performance predictions of redox flow batteries that match the experimental measurement. The model is now ready to be taken forward to help design optimal electrode structures. In a first step we examined three electrodes with different porous structures. We revealed that a porous structure with uniform pore size distribution around a dominant pore size peak around 20 micrometer and a small fraction of larger pores is beneficial. We have a joint publication to be published soon with Journal of Power Sources.
Start Year 2018