1. OXIS Energy Ltd
Li-S Batteries for Energy Storage Applications
Dr David Ainsworth, Chief Technical Officer
Frontier Energy Storage Technologies and Global
Energy Challenges
11th May 2016

2. OXIS Company Background
 $70 million investment since 2005
 Expanding rapidly:
 3 fold increase in the number of employees since 2012 =>
59 today
 Highly trained staff (14 PhDs, 13 MSc/MA)
 Cutting edge development facilities => second largest high
specification dry room in Europe
 Strong patent portfolio protecting IP => 79 patents
granted, 81 pending, encompassing 25 families)
 OXIS have been working on Li-S since 2005 at Culham
Science Centre (Oxfordshire, UK)

3.  High Gravimetric Energy
• Theoretical 2500 Wh kg-1
• >400 Wh kg-1 achievable in the future
 Low Predicted Costs
 High Safety
• Short Circuit Test
• Nail Penetration Test
• Overcharge
• Thermal Stability
 Producing Li-S battery cells at pilot scale 
Internally at OXIS and at manufacturing
partners
OXIS Li-S Pouch Cell Technology
Variety of different sizes
and capacities
2.0 – 3.4 Ah
6 Ah – 10 Ah
> 20 Ah
10Ah Li-S pouch cells 3 KWh Li-S Rack
Mounted Battery System

4. Introduction
 Overview of Li-S cell technology
 Key considerations for energy storage applications
 OXIS materials research activities
 OXIS activities relating to energy storage
 Concluding remarks

5. Overview of Li-S Technology

6. Company Confidential
Li-S Batteries: Principles
Li
Currentcollector
Currentcollector
Li+
Li+
Li+
Li+
Li+
Li+
(-) (+)
Separator
+-
Discharge
Load /
Charger
S8
(-) : 16 Li° → 16 Li+ + 16 e-
(+) : S8 + 16 e- → 8 S2-
16 Li° + S8 → 8 Li2S
Elemental sulfur
Conductive
carbon
Binder
 Average voltage:
2.1 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

7. OXIS Key Technical Competences
R&D Pilot Production Battery Systems
Materials Research Li-S Cell and Components Battery Design and Testing

8. History of OXIS Li-S Cell Development
Q2 2015: 10Ah Cell
Energy Storage/LEV’s
160Wh/kg
2010: 500 mAh
pouch cell
< 100 Wh/kg
Q4 2014:39Ah
automotive cell
220 Wh/kg
2011-2013: 1.7-3.4Ah
pouch cells
170 Wh/Kg
Q1 2015: Ultra light
for UAV market
35 Ah ; 300 Wh/kg
ULTRALIGHTLONGLIFE
Q3 2014: 25Ah
automotive cells
200 Wh/Kg
Q4 2014: Ultra light
for UAV market
6.5 Ah ; 265 Wh/kg
2013-2014: R&D
prototype
2 Ah ; 220-240 Wh/kg
Q2 2015: Ultra light
for UAV market
21 Ah ; 325 Wh/kg
Company Confidential

9. Improvements to Li-S Technology
 OXIS is researching the following areas to
improve cell performances
 Sulfur/Carbons/Binders
 Current collectors
 Separators
 Lithium & protection mechanisms
 Electrolytes
Current Collector
Sulfur/Carbon/Binder
Electrolyte
Separator
Lithium
Current Collector
Cathode
Anode
SeparatorSulfur/Carbon/Binder
Ni Tab
Al Tab
Cathode
Anode
Separator
Pouch
 20 R&D scientists (11 PhD’s)
 20 production staff
 Aiming to achieve 500Wh/Kg by 2020

10. Li-S Cells for Energy Storage
 Over 1400 cycles demonstrated on OXIS Long-Life Li-S cells

11. Key Considerations of Energy Storage

12. Considerations for Li-S Batteries in Energy Storage
 Cost per KWh => > $200/KWh at over 3M units production
 Cycle Life => 1400 cycles today, targeting 2000 cycles
 Recyclability => No heavy/transition metals, lithium probable only material of value
 Price per kWh of energy storage is key! => Strongly dependant of deployed location

13. Considerations for Li-S Batteries in Energy Storage
Other, 5% Separator,
5%
Lithium,
15%
Cathode,
25%
Electrolyte
50%
A typical distribution of
masses in an Li-S cell
 Electrolyte can represent up to 50% of
the weight of a cell!
 Electrolyte and Lithium are most
expensive cell components
Sulfur can only represent up
to 15% of the mass of the cell

14. Materials Research Activities

15. Optimisation of Li-S cells from Materials Research
Cathode:
New S/C composites
• Increase S8 loading
• Increase S8 utilisation
• Improve power capability
Electrolyte:
Development of new additives and
solvents
• Maintain Safety
• Increase S8 utilisation
• Stability vs Anode
Anode:
New anode coating
• Enhance cycle life
• High resistance to corrosion
• Reduce electrolyte degradation
• Increase volumetric energy

16. Anodes for Li-S Batteries: Cycle Life
Coated Lithium Anode
Solution => Deposit thin protective coating onto
anode surface
Required Properties:
 Good adhesion to lithium metal
 High sheer modulus
 High ionic conductivity
 Chemical resistance

17. Development of Protected Lithium Metal Anodes
Unprotected Lithium: 50 cycles Protected Lithium: 50 cycles
Very aggressive conditions
High surface area lithium
Integrity of foil is preserved

18. Cathode Development: Energy Density and Cost
TEM image of Sulfur/CNT composite material
Issues:
 Both Sulfur and Lithium are insulating
 Low surface capacity for good utilization
 Access/Wettability of active material
 Power
 Migration of Polysulfides
Solutions:
 Form 3D conductive network form S/CNT
composite
 Functionalization of binder/carbon materials?
 Control process parameters to tailor cathode
porosity/ morphology

19. Energy Storage Activities at OXIS Energy

20. OXIS Li-S Battery Evolution
Bike Battery V2
using 3.4 Ah cells
2013
Rack Mount Battery
using 10 Ah cells
2016
Control Board
Very simple safety
circuitry
Components = 58
Bike Battery V1
using 1.7 Ah cells
2012
Stackable Battery
using 3.4 Ah cells
2015
Navya
using 3.4 Ah cells
2014
LINCAD BMS
Adapted from LIPS10
RDVS BMS
Cell Control Board
Balancing and Safety
per cell
Components = 101
Control Board
Prototype only
Enhanced safety
Communications
Components = 261
Control Board with
integrated cell monitoring
Production
Safety + reliability (fault
diagnostics)
Components = 897
Cell Wiring Board
Production orientated
connectivity. Board per
module
Charger Board
For direct PV
connection
LIPS 10 Battery
Development for MoD

21. Li-S Batteries for Stationary Energy Storage
3KWh Rack
Mounted Battery
48KWh Battery
System
1MWh Containerised
Battery System

22. 3 kWh Rack Mounted Battery
• Prototype 1 of 3KWh Rack Mounted Battery manufactured in Q1 2016
– Prototype battery completed and initial tests successful
N.B. Flying leads are deliberate to allow testing of the prototype

23. 3 kWh Rack Mount Battery Specification
Dimensions (h x w x d) 130 x 482 x 650 mm
Weight 25 kg
Cell type OXIS POA0122 10Ah Long-Life Lithium-Sulfur cells
Number of cells 144
Environmental protection IP 20
Storage temperature -27 to + 30 °C
Operating temperature 0 to 60 °C
Nominal voltage 50 V
Minimum voltage 38 V
Maximum voltage 56.4 V
Rated stored energy 3 kWh Charge 0.1C, discharge 0.2C
Usable stored energy 2.5 kWh Charge 0.1C, discharge 0.2C
Rated capacity 60 Ah Charge 0.1C, discharge 0.2C
Operating Depth of Discharge (DoD) 80 %
Maximum continuous discharge current 60 A
Peak discharge current (30 secs max) 180 A
Maximum charging current 15 A
Recommended charging current 6 A
Equivalent series resistance < 100 mΩ
Isolation to chassis 1 kV
Cycle life 1400 cycles Charge 0.1C, discharge 0.2C, 80% DoD.
Battery equivalent series resistance < 100 mΩ
Features:
• Cell balancing
• Cell safety monitoring circuits with redundancy
• Electronic short circuit protection (LV only)
• High voltage interlock/ trip (HV only)
• Chassis isolation monitor
• Isolated user CAN bus interface
• Isolated user RS485 bus interface
• Ethernet port
• Internal history and fault logging

24. Master Controller
Battery System Architecture
System Integrator responsibility
OXIS custom design and manufacture
OXIS standard design, 3rd party manufacture
Key
RMB
RMB
RMB
RMB
RMB
RMB
RMB
RMB
SC
Rack 1
RMB
RMB
RMB
RMB
RMB
RMB
RMB
RMB
SC
Container
RMB
RMB
RMB
RMB
RMB
RMB
RMB
RMB
SC
Rack 21
RMB
RMB
RMB
RMB
RMB
RMB
RMB
RMB
SC
RMB
RMB
RMB
RMB
RMB
RMB
RMB
RMB
SC
Rack 2
RMB
RMB
RMB
RMB
RMB
RMB
RMB
RMB
SC
Inverter and grid
connection
RMB Rack Mount Battery
SC String Controller

25. Conclusions
 Li-S Cells need to be low cost and long cycle life for Energy Storage
 Costs of <$200/kWh are already possible at mass manufacturing scale
 Cathode/Electrolyte Interface for reduced cost plus lithium protection for extended cycle life
 Prototype Li-S battery systems for stationary energy storage are being tested by OXIS

26. OXIS R&D Development Partners
Joint Development
Agreements
Development
Programmes
Partnerships

27. Mark Wild
Geraint Minton
Laura O’Neill
Rajlakshmi Purkayastha
Steffen Schlueter
Sylwia Walus
David Ainsworth
Agata Swiatek
Ashley Cooke
Jacob Locke
Justyna Kreis
Lisset Urrutia
Lukasz Kabacik
Martin Clegg
Lukasz Solek
Maciej Szczygielski
Sebastien Desilani
Sebastien Liatard
Stephen Lawes
Steve Rowlands
Acknowledgements