Administration Admin Open Recorded Your hosts Discussion - - PowerPoint PPT Presentation

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Get Involved

Open Discussion

Recorded

Exchange Ideas Research Frontiers

Enjoy Meet Eureka! Questions Publication

Administration

Organiser Speaker Press

Dr Gregory Offer Dr George Crabtree

Your hosts

 Joined Oxis in 2009 appointed CTO in 2013  MBA and PhD (Chemistry)  Manages team of R&D scientists improving and scaling up lithium sulfur battery technology

Dr David Ainsworth

Admin

 Argonne National Lab Distinguished Fellow  Director Joint Centre Energy Storage Research JCESR in USA  Directs the overall strategy and goals of the research program and operational plan  Academic at Imperial College London since 2010  Group works at interface of science and engineering of electrochemical devices  Testing and modelling lithium sulfur cells alongside other storage technologies

Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Jack Nicholls

 Programme Manager at Oxis  Conference Organiser

Tom Cleaver

Admin

 Events Officer at Imperial  Conference Organiser

Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Your hosts

Central London This evening

Your venue

 One of the world’s largest engineering institutions with

• ver 168,000 members in 150

countries  Mission is to inspire, inform and influence the global engineering community  Savoy Place, just finished two year refurbishment

Admin

 Evening reception on amazing roof terrace with spectacular view  Free drinks, please be responsible  Dress warm if you want to stand

• utside

 Walking distance to  Houses of Parliament  Buckingham Palace  Covent Garden  Multiple Theatres, Restaurants  St Paul’s Cathedral  etc

Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

The IET

Aim of the conference

• Established to provide a forum for everyone working on lithium sulfur technologies to meet and present

Academic content

 Mechanisms  1 keynote lecture  2 parallel sessions  Modelling  1 keynote lecture  1 parallel session  Materials  1 keynote lecture  3 parallel sessions  Applications  1 keynote lecture  1 plenary session

General Aims

Networking

 Promote communication  Socializing time/space  Knowledge transfer  Presentations  Poster sessions  Discussion  Question & Answer  Please engage  Disseminate  Videos  Publications  New relationships

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Changes from last year

• Most presentations will be recorded and put online after the conference:

 Only with permission of the presenter  Significantly increases the impact of YOUR work

• All work presented at the conference can be submitted to a special focus issue of ECS:

 Edited by Professor Doron Aurbach, assisted by the conference hosts  Deadline for submissions after conference 21st August 2017  Papers can be submitted earlier, and will be published online into an “issue in progress” within around 10 days of being accepted after peer review  This focus issue will be open access (OA) at no cost to the authors, as part of the Society’s ongoing Free the Science initiative  Significantly increases the impact of YOUR work  Please contact us if you are a presenter (oral or poster) and have not received an invite

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Sponsors

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Drinks Sponsor & Exhibitor Exhibitors Sponsor

Lithium sulfur vs. lithium ion

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications 2.5 3 3.5 4 20 40 60 80 100 Voltage Discharge Capacity (%)

Characteristic Li-Ion Discharge Profile

1.9 2 2.1 2.2 2.3 2.4 20 40 60 80 100 Voltage Discharge Capacity (%)

Characteristic Li-S Discharge Profile

• Average voltage:

2.15 V (vs. 3.7 V of Li-ion)

• Sulfur electrode specific capacity:

1675 mAh g-1 (vs. 170 mAh g-1 of LiFePO4)

• Complex working mechanism: with

intermediate species (soluble Li2Sx)

• Theoretical gravimetric and

volumetric energy: 2500 Wh kg-1 and 2800 Wh L-1, respectively. (vs. 570 Wh kg-1 and 2000 Wh L-1 of LiFePO4) Li-S considerations

• S8 and Li2S electronically insulating
• Shuttle of soluble polysulphide

intermediates

• Dendritic lithium growth and

reactivity of lithium with electrolyte.

A very complex working mechanism

 Precipitations/dissolution cycles (solid ↔ liquid phases)

Limitations → Challenges (!)

Cathode Electrolyte Anode (Li)

• Mossy Li
• Unstable interface
• Low S8 conductivity
• Dissolution of active material
• Passivation by insulating Li2S
• Solvent/polysulfides interactions
• Shuttle mechanism
• Viscosity (→ resistance) variations

(Epractical << Etheoretical)

Li-S Cells: Basic Principles

(-) : 16 Li° → 16 Li+ + 16 e- (+) : S8 + 16 e- → 8 S2-

16 Li° + S8 → 8 Li2S

 High gravimetric energy (expected: 300 – 600 Wh kg-1)  Low cost and availability of sulfur

Why Li-S batteries…?

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

A very complex working mechanism

 Precipitations/dissolution cycles (solid ↔ liquid phases)

Limitations → Challenges (!)

Cathode Electrolyte Anode (Li)

• Mossy Li
• Unstable interface
• Low S8 conductivity
• Dissolution of active material
• Passivation by insulating Li2S
• Solvent/polysulfides interactions
• Shuttle mechanism
• Viscosity (→ resistance) variations

(Epractical << Etheoretical)

Li-S Cells: Basic Principles

(-) : 16 Li° → 16 Li+ + 16 e- (+) : S8 + 16 e- → 8 S2-

16 Li° + S8 → 8 Li2S

 High gravimetric energy (expected: 300 – 600 Wh kg-1)  Low cost and availability of sulfur

Why Li-S batteries…?

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Why lithium sulfur batteries?

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Currently suited to applications that value low mass over volume aerospace/space some vehicles portable batteries

• One of the lightest rechargeable battery chemistries

Lithium sulfur operational challenges

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

• Lower nominal voltage
• A solution chemistry
• A more complex

mechanism

• More difficult to determine

SoC

• Voltage sometimes

increases during discharge

• Resistance changes dramatically too

Zhang et al, Phys. Chem. Chem. Phys., 2015, Vol 17, Issue 35, 22581-22586

A very complex working mechanism

 Precipitations/dissolution cycles (solid ↔ liquid phases)

Limitations → Challenges (!)

Cathode Electrolyte Anode (Li)

• Mossy Li
• Unstable interface
• Low S8 conductivity
• Dissolution of active material
• Passivation by insulating Li2S
• Solvent/polysulfides interactions
• Shuttle mechanism
• Viscosity (→ resistance) variations

(Epractical << Etheoretical)

Li-S Cells: Basic Principles

(-) : 16 Li° → 16 Li+ + 16 e- (+) : S8 + 16 e- → 8 S2-

16 Li° + S8 → 8 Li2S

 High gravimetric energy (expected: 300 – 600 Wh kg-1)  Low cost and availability of sulfur

Why Li-S batteries…?

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

A very complex working mechanism

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

High Plateau (Ca. 4 e-) First Cycle, dissolution and 2 step reduction S8 (S) + 2e- + 2Li+ → Li2S8 (soln) Reductive Dissociation Li2S8 + 2e- + 2Li+ → Li2S6 + Li2S2 (or) Li2S8 + 2e- + 2Li+ → 2Li2S4 Low Plateau (12-n e-) Chemical Equilibrium Li2S6 ↔ 2LiS3

. (radical)

Dominating low plateau electrochemical reaction LiS3

. + e- + Li+→ Li2S3

Association and precipitation Li2S3 + Li2S4→ Li2S6 + Li2S (S) And many other reactions Inaccessible Capacity (n e-) Equilibrium conc. of unreacted intermediates Li2Sn (Soln.) + Li2S (S) Irreversible Capacity Loss Polysulfide oxidation Lithium solvent/salt reactions SEI formation and re-formation Loss of active surface area Electrically isolated precipitation And many other reactions

Mark Wild, Laura O’Neill, Teng Zhang, Rajlakshmi Purkayastha, Geraint Minton, Monica Marinescu, Gregory J. Offer., Energy & Environmental Science; 2015, volume 8, issue 12, pages 3477-3494.

• Strongly dependent on cell design (and each component)

Cathode

 Confined/host structure  Open/simpler architecture (easier to scale-up)

Electrolyte

 Solvent nature

• Chemical interactions with Li2Sx
• Affects solubility/precipitation of different Li2Sx species
• Influences stability of different Li2Sx species (i.e. S3
• -)

 Salt type and molarity

Sulfur/Electrolyte ratio

Does a ‘Universal’ Working Mechanism Exist?

[1] M. Cuisinier et al, Energy Environ. Sci., 7 (2014) 2697 [2] L. Suo et al, Nat. Commun., 4 (2013) 1481. [3] A. Manthiram et al., Acc. Chem. Res., 46 (2012) 1125-1134

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

A very complex working mechanism

 Precipitations/dissolution cycles (solid ↔ liquid phases)

Limitations → Challenges (!)

Cathode Electrolyte Anode (Li)

• Mossy Li
• Unstable interface
• Low S8 conductivity
• Dissolution of active material
• Passivation by insulating Li2S
• Solvent/polysulfides interactions
• Shuttle mechanism
• Viscosity (→ resistance) variations

(Epractical << Etheoretical)

Li-S Cells: Basic Principles

(-) : 16 Li° → 16 Li+ + 16 e- (+) : S8 + 16 e- → 8 S2-

16 Li° + S8 → 8 Li2S

 High gravimetric energy (expected: 300 – 600 Wh kg-1)  Low cost and availability of sulfur

Why Li-S batteries…?

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Challenges to overcome

• Is the community focusing on the right things:

Increasing energy density  This sounds good, or is 400 Wh/kg already good enough (for now) Reducing degradation  This would be good BUT the power limitation means it will take years to prove Should we focus on power density first, and then degradation  Faster cycling means faster testing

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Lithium sulfur research

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

• Increasing research into

this area

• Exponential increase in

academic papers being published

43 78 150 304 515 729 932 2010 2011 2012 2013 2014 2015 2016

Search on science direct for “lithium sulfur battery” on 20th April 2017

• Increasing research into this area:

Industrial  Oxis  Sion  NOHMs  Sony  LGChem Academic groups  Exponential increase

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

• Reviewed >1,000 papers so far

 Done up to 2014  Target 2,000 and complete 2015 & 2016  Paper will be submitted to the ECS special issue

Lithium sulfur research

• Research is focused on:

New materials  Carbons & conductive framework  Anode Coatings, Interlayers  Electrolytes, Solvents, Salts & Additives How they work  Mechanisms  Modelling

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Lithium sulfur research

• Research is focused on:

New materials  Carbons & conductive framework  Anode Coatings, Interlayers  Electrolytes, Solvents, Salts & Additives How they work  Mechanisms  Modelling Some very obvious gaps  Relatively little on understanding charging, yet that is what a battery does half the time!  Manufacturing, production methods and scaling up is often neglected  Anode is poorly studied, yet crucial to understand degradation

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Lithium sulfur research

• Understanding of a Li-S cell…

Towards Practical Applications…

Li-S Battery Pack Li-S Cell

Cell integration

[1] S. Walus et al. ChemComm 2013, 49(72) 7899-7901 [2] M. Cuisinier et al., J. Phys. Chem. Lett., 4 (2013) 3227-3232 [3] M. Patel et al., ChemSusChem 2013, 6(7) 1177-1181 [4] N.A. Cañas et al., J. Phys. Chem. C, 118 (2014) 12106-12114

Mechanistic insight

• In situ and operando characterisation techniques

(tremendous work is reported in the literature!)

• Bespoke cell design: may be far from realistic conditions
• Coin cells or small pouches ≠ Large format cells
• …on a complete cell level

Li2Sx

• Cycling performances at optimized conditions
• Thermal characteristics
• Cell expansion
• Storage conditions
• Safety
• …

Scaling up from a coin cell to a pouch cell

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

• How can we influence cycle life?
• How can we influence energy density?
• How can we influence power performance?
• How can we influence thermal performance?
• How do we influence the shape of the discharge curve?
• How do we influence charge efficiency?
• How do we better understand experimental results?
• How do we predict behaviour?
• How can we better understand the needs of applications?
• How can we scale up production?

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Multiple research questions remain

• Cathode issues:
• S8 and Li2S are insulating  requires intimate contact with carbon
• Large volumetric changes  risk of structure collapsing

 Dissolution of Li2Sx  Precipitation of solid/insulating Li2S and S8

• Low sulfur utilization (mAh g-1) at high surface capacity (mAh cm-2)
• Solutions → many have been proposed
• 3D conductive network (CNT/S)
• Functionalized materials (binders/carbons)
• Tailoring cathode porosity/morphology
• …and many more

Literature brief state-of-art of cathode architecture

[1] L. Suo et al, Nat. Commun., 4 (2013) 1481. [2] A. Manthiram et al., Acc. Chem. Res., 46 (2012) 1125-1134

Before cycling After discharge

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Cathode development challenges

Key component

• f a Li-S cell

[2] M.R. Busche et al. J. Power Sources 2014, 259: 289-299

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Electrolyte development challenges

Mechanistic Perspective

• Electrolyte - where all

the chemical and electrochemical reactions occur

• Significantly affect the mechanisms and

reactions pathways

• Enhance/inhibit shuttle mechanism
• Influence on Li2S precipitation
• Affect S8 utilisation (= discharge capacity)
• Type & volume of the electrolyte may:

[1] W. Kang et al. Nanoscale, 2016,8, 16541-16588

Key component

• f a Li-S cell

Mechanistic Perspective Specific Energy/ Cell design

• Electrolyte - where all

the chemical and electrochemical reactions occur

• Significant effect on the cell

specific energy

• Approximate Li-S cell mass breakdown
• Significantly affect the mechanisms and

reactions pathways

• Enhance/inhibit shuttle mechanism
• Influence on Li2S precipitation
• Affect S8 utilisation (= discharge capacity)
• Type & volume of the electrolyte may:

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Electrolyte development challenges

[1] W. Kang et al. Nanoscale, 2016,8, 16541-16588

Understanding the mechanism(s)

• Experimental techniques used for revealing the mechanism(s):
• Combined with

Computational analysis

 X-Ray Diffraction (XRD)  Ultraviolet-Visible Spectroscopy (UV-Vis)  Raman Spectroscopy  Electron Paramagnetic Resonance (EPR)  X-Ray Absorption Spectroscopy (XAS)  Nuclear Magnetic Resonance (NMR)  High Performance Liquid Chromatography (HPLC)  Rotating-Ring Disk Electrode (RRDE)  Transmission X-ray Microscopy (TXM)  …..  ..

[1] M. Cuisinier et al., J. Phys. Chem. Lett., 4 (2013) 3227-3232 [2] Y.-C. Lu et al., J. Phys. Chem. C, 118 (2014) 5733-5741 [3] C. Barchasz et al., Anal. Chem., 84 (2012) 3973-3980 [4] N.A. Cañas et al., J. Phys. Chem. C, 118 (2014) 12106-12114

• In situ
• Ex situ
• Operando
• Solid phases (S8, Li2S)
• Soluble species (Li2Sx)
• Combination of both
• Bespoke cell

design

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

Modelling

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

[1] Thangavel et al, J. Electrochem Soc. 163 (2016). [3] Marinescu., Phys. Chem. Chem. Phys. 18 (2016). [2] Danner et al, Electrochimica Acta 184 (2015). [4] Ren et al, J. Power Sources 336 (2016). [2] [4]

• Identify limiting mechanisms, predict battery performance
• Focusing on
• Reaction kinetics and shuttle
• Precipitation/dissolution
• C/S morphology
• Many more challenges
• Thermal coupling
• Degradation mechanisms
• Parameterization & validation
• ….

Applications

Admin Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials Mechanism Modelling Applications

• Different applications have different needs

Li-S key characteristics compared to Li-ion  High specific energy Moderate volumetric energy? Moderate power?  Low cost? Li-S will be better suited to certain types of systems where mass is more important than volume.  The systems designers are best placed to advise what they need Introduction to market is likely to be initially low volume, niche capability, high cost; moving towards higher volumes, better capabilities and lower costs

• Low power & cycle life systems first
• Higher power & cycle life to follow

Agenda

Today 1000

• 1. Mechanism Keynote

1030 Tea Break 1100 2a Mechanism Panel Session (in here) 2b Materials Panel (Blumlein) 1300 Lunch 1400

• 3. Modelling Keynote

1435 4a Modelling Panel Session (in here) 4b Materials Panel (Blumlein) 1535 Tea Break 1600 4a Modelling Panel Session (in here) 4b Materials Panel (Blumlein) 1700

• 5. Poster Session (Drinks from 1730, sponsored by Maccor)

1830 Dinner & drinks (Riverside room & roof terrace) 2300 Depart

Agenda – Poster Session

Modelling Mechanism Materials Applications Materials

Agenda

Tomorrow 0900 Registration 0930

• 6. Materials Keynote

1005 7a Materials Panel Session (in here) 7b Mechanism Panel (Blumlein) 1105 Tea Break 1130 7a Materials Panel Session (in here) 7b Mechanism Panel (Blumlein) 1250 Lunch 1350

• 8. Applications Session (in here)

1520 Closing remarks

2018

2018 Save the Date! 25-26 April 2018

Venue to be confirmed