Administration Admin Open Recorded Your hosts Discussion - PowerPoint PPT Presentation

Administration Admin Open Recorded Your hosts Discussion Publication Questions Research Exchange Frontiers Get Eureka! Meet Your venue Ideas Enjoy Involved Conference Basic Principles Lithium Sulfur Outlook Materials Organiser Mechanism Speaker Modelling Press Applications

Your hosts Admin Dr David Ainsworth Dr Gregory Offer Dr George Crabtree Your hosts Your venue Conference Basic Principles Lithium Sulfur  Joined Oxis in 2009 appointed  Argonne National Lab  Academic at Imperial College Outlook CTO in 2013 Distinguished Fellow London since 2010  MBA and PhD (Chemistry)  Director Joint Centre Energy  Group works at interface of Materials  Manages team of R&D scientists Storage Research JCESR in USA science and engineering of  Directs the overall strategy and improving and scaling up lithium electrochemical devices Mechanism  Testing and modelling lithium sulfur battery technology goals of the research program and operational plan sulfur cells alongside other Modelling storage technologies Applications

Your hosts Admin Tom Cleaver Jack Nicholls Your hosts Your venue Conference Basic Principles Lithium Sulfur Outlook Materials  Events Officer at Imperial  Programme Manager at Oxis  Conference Organiser  Conference Organiser Mechanism Modelling Applications

Your venue Admin The IET Central London This evening Your hosts Your venue Conference Basic Principles Lithium Sulfur  One of the world’s largest Outlook  Evening reception on amazing  Walking distance to engineering institutions with  Houses of Parliament roof terrace with spectacular over 168,000 members in 150 Materials  Buckingham Palace view countries  Free drinks, please be  Covent Garden  Mission is to inspire, inform and  Multiple Theatres, Restaurants Mechanism responsible influence the global engineering  Dress warm if you want to stand  St Paul’s Cathedral community  etc outside Modelling  Savoy Place, just finished two year refurbishment Applications

Aim of the conference  Established to provide a forum for everyone working on lithium sulfur technologies to meet and present Admin Academic content General Aims Your hosts  Promote communication  Mechanisms  1 keynote lecture  Socializing time/space Your venue  2 parallel sessions  Knowledge transfer  Modelling  Presentations Conference  1 keynote lecture  Poster sessions  Discussion  1 parallel session Basic Principles Lithium Sulfur  Materials  Question & Answer  1 keynote lecture  Please engage Outlook  Disseminate  3 parallel sessions  Applications  Videos Materials  Publications  1 keynote lecture  1 plenary session  New relationships Mechanism Modelling Networking Applications

Changes from last year  Most presentations will be recorded and put online after the conference: Admin  Only with permission of the presenter  Significantly increases the impact of YOUR work Your hosts  All work presented at the conference can be submitted to a special focus issue of ECS: Your venue  Edited by Professor Doron Aurbach, assisted by the conference hosts  Deadline for submissions after conference 21 st August 2017 Conference  Papers can be submitted earlier, and will be published online into an “issue in progress” within around 10 days of being acce pted after peer review Basic Principles  This focus issue will be open access (OA) at no cost to the authors, as part of the Society’s ongoing Free the Science initia tive Lithium Sulfur  Significantly increases the impact of YOUR work  Please contact us if you are a presenter (oral or poster) and have not received an invite Outlook Materials Mechanism Modelling Applications

Sponsors Admin Drinks Sponsor & Exhibitor Your hosts Your venue Conference Sponsor Basic Principles Lithium Sulfur Outlook Materials Exhibitors Mechanism Modelling Applications

Lithium sulfur vs. lithium ion  Admin Average voltage: 2.15 V ( vs. 3.7 V of Li-ion)  Sulfur electrode specific capacity: Your hosts 1675 mAh g -1 ( vs. 170 mAh g -1 of LiFePO 4 ) Your venue  Complex working mechanism: with intermediate species (soluble Li 2 S x ) Conference  Theoretical gravimetric and volumetric energy: 2500 Wh kg -1 and Basic Principles Lithium Sulfur 2800 Wh L -1 , respectively. ( vs. 570 Wh kg -1 and 2000 Wh L -1 of LiFePO 4 ) Outlook Characteristic Li-S Discharge Profile Characteristic Li-Ion Discharge Profile 2.4 Li-S considerations Materials 4 2.3  S 8 and Li 2 S electronically insulating Voltage 2.2 Mechanism Voltage 3.5  Shuttle of soluble polysulphide 2.1 intermediates 3 Modelling  Dendritic lithium growth and 2 reactivity of lithium with electrolyte. 2.5 1.9 Applications 0 20 40 60 80 100 0 20 40 60 80 100 Discharge Capacity (%) Discharge Capacity (%)

Li-S Cells: Basic Principles A very complex Limitations → Challenges (!) Admin Why Li- S batteries…? (E practical << E theoretical ) working mechanism Your hosts Cathode  High gravimetric energy  Precipitations/dissolution cycles (expected: 300 – 600 Wh kg -1 ) (solid ↔ liquid phases) • Low S 8 conductivity Your venue  Low cost and availability of sulfur • Dissolution of active material • Passivation by insulating Li 2 S Conference Electrolyte Basic Principles Lithium Sulfur • Solvent/polysulfides interactions Outlook • Shuttle mechanism • Viscosity ( → resistance) variations Materials Anode (Li) Mechanism • Mossy Li (-) : 16 Li° → 16 Li + + 16 e - • Unstable interface Modelling (+) : S 8 + 16 e - → 8 S 2- 16 Li° + S 8 → 8 Li 2 S Applications

Li-S Cells: Basic Principles A very complex Limitations → Challenges (!) Admin Why Li- S batteries…? (E practical << E theoretical ) working mechanism Your hosts Cathode  High gravimetric energy  Precipitations/dissolution cycles (expected: 300 – 600 Wh kg -1 ) (solid ↔ liquid phases) • Low S 8 conductivity Your venue  Low cost and availability of sulfur • Dissolution of active material • Passivation by insulating Li 2 S Conference Electrolyte Basic Principles Lithium Sulfur • Solvent/polysulfides interactions Outlook • Shuttle mechanism • Viscosity ( → resistance) variations Materials Anode (Li) Mechanism • Mossy Li (-) : 16 Li° → 16 Li + + 16 e - • Unstable interface Modelling (+) : S 8 + 16 e - → 8 S 2- 16 Li° + S 8 → 8 Li 2 S Applications

Why lithium sulfur batteries? • One of the lightest rechargeable battery chemistries Admin  Currently suited to Your hosts applications that value Your venue low mass over volume Conference  aerospace/space Basic Principles Lithium Sulfur  some vehicles Outlook  portable batteries Materials Mechanism Modelling Applications

Lithium sulfur operational challenges Admin • Lower nominal voltage Your hosts • A solution chemistry Your venue • A more complex Conference mechanism Basic Principles • More difficult to determine Lithium Sulfur SoC Outlook • Voltage sometimes Materials increases during discharge Mechanism • Resistance changes dramatically too Modelling Zhang et al, Phys. Chem. Chem. Phys., 2015, Vol 17, Issue 35, 22581-22586 Applications

Li-S Cells: Basic Principles A very complex Limitations → Challenges (!) Admin Why Li- S batteries…? (E practical << E theoretical ) working mechanism Your hosts Cathode  High gravimetric energy  Precipitations/dissolution cycles (expected: 300 – 600 Wh kg -1 ) (solid ↔ liquid phases) • Low S 8 conductivity Your venue  Low cost and availability of sulfur • Dissolution of active material • Passivation by insulating Li 2 S Conference Electrolyte Basic Principles Lithium Sulfur • Solvent/polysulfides interactions Outlook • Shuttle mechanism • Viscosity ( → resistance) variations Materials Anode (Li) Mechanism • Mossy Li (-) : 16 Li° → 16 Li + + 16 e - • Unstable interface Modelling (+) : S 8 + 16 e - → 8 S 2- 16 Li° + S 8 → 8 Li 2 S Applications

A very complex working mechanism Admin (Ca. 4 e - ) (12-n e - ) Inaccessible Capacity (n e - ) High Plateau Low Plateau Your hosts First Cycle, dissolution and 2 Chemical Equilibrium Equilibrium conc. of unreacted . (radical) step reduction Li 2 S 6 ↔ 2LiS 3 intermediates Your venue S 8 (S) + 2e - + 2Li + → Li 2 S 8 (soln) Li 2 S n (Soln.) + Li 2 S (S) Dominating low plateau Conference Reductive Dissociation electrochemical reaction Irreversible Capacity Loss Li 2 S 8 + 2e - + 2Li + → Li 2 S 6 + Li 2 S 2 . + e - + Li + → Li 2 S 3 Basic Principles LiS 3 Polysulfide oxidation Lithium Sulfur (or) Lithium solvent/salt reactions Association and precipitation Li 2 S 8 + 2e - + 2Li + → 2Li 2 S 4 Outlook SEI formation and re-formation Li 2 S 3 + Li 2 S 4 → Li 2 S 6 + Li 2 S (S) Loss of active surface area Materials And many other reactions Electrically isolated precipitation Mechanism And many other reactions Modelling 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. Applications