The UK Energy Storage Supergen Consortium Prof Peter Hall Dept Chemical Engineering University of Strathclyde Glasgow Scotland

Need for Energy Storage  Even though UK energy grid is based upon centralised power sources there is considerable energy storage built into system  Coal stocks peaked at 24,000 kTonnes at end of 2009 (~55,000 GWh electrical)  Pumped hydro only accounts for equivalent of 3,500 Tonnes coal  Electrification of transport will double electrical demand and have immediate effect on CO 2 emissions

Supergen partnership  Six Universities:  Fundamental materials understanding: Cambridge, Bath  Materials, device production: St Andrews, Strathclyde, Newcastle  Materials scale-up: Oxford, Strathclyde  Transport engineering: Strathclyde  Grid engineering: Bath

Technology problem areas  High cost/low energy density of Li based batteries  Most supercapacitors manufacturers base technology around organic liquid electrolytes  Low voltage devices (~6-7 V)  High production costs  Technology awareness and applications

Anode Li Cathode O 2 Organic Electrolyte Li + O2O2 Li 2 O 2 Carbon Electrode 2Li + + 2e - + O 2  Li 2 O 2 Li battery research Li/O 2 cells

V total = cm 3 /g S BET = 1725 m 2 /g PS = 5.60 nm V total = cm 3 /g S BET = 1545 m 2 /g PS = 6.10 nm V total = cm 3 /g S BET = 1290 m 2 /g PS = 6.15 nm Capacity of Li ion batteries Increased capacity Li/O 2 battery performance

Charge / Discharge cycling of ACRF carbon

Supercapacitor research  Developments to increase performance/cost ratio include  Aqueous electrolyte devices based on high grade carbons  Ionic liquid based supercapacitors  Development of pseudocapacitors  Future developments are materials based

Battery lifetime extension

Materials structure/performance Sample2 mA 4 mA 8 mA 16 mA 32 mA 64 mA E max Wh/g EMImBF 4 Capacitance F/g ACRF ACRF ACRF ACRF

Conclusions/Plans  Substantial materials developments have taken place  Rechargeable Li/O 2 cells have been demonstrated at the button cell level  Our aim is to produce viable pouch cells within three years  Fundamental improvements have been made to the understanding of mass transfer in ionic liquid based supercapacitors  We aim to produce commercial aqueous bipolar supercapacitors within two years