title: Thermoelectric Power Generation from Lanthanum Strontium Titanium Oxide at Room Temperature through the Addition of Graphene.
abstract: The applications of strontium titanium oxide based thermoelectric materials are currently limited by their high operating temperatures of >700 °C. Herein, we show that the thermal operating window of lanthanum strontium titanium oxide (LSTO) can be reduced to room temperature by the addition of a small amount of graphene. This increase in operating performance will enable future applications such as generators in vehicles and other sectors. The LSTO composites incorporated one percent or less of graphene and were sintered under an argon/hydrogen atmosphere. The resultant materials were reduced and possessed a multiphase structure with nanosized grains. The thermal conductivity of the nanocomposites decreased upon the addition of graphene, whereas the electrical conductivity and power factor both increased significantly. These factors, together with a moderate Seebeck coefficient, meant that a high power factor of ∼2500 μWm(-1)K(-2) was reached at room temperature at a loading of 0.6 wt % graphene. The highest thermoelectric figure of merit (ZT) was achieved when 0.6 wt % graphene was added (ZT = 0.42 at room temperature and 0.36 at 750 °C), with >280% enhancement compared to that of pure LSTO. A preliminary 7-couple device was produced using bismuth strontium cobalt oxide/graphene-LSTO pucks. This device had a Seebeck coefficient of ∼1500 μV/K and an open voltage of 600 mV at a mean temperature of 219 °C.
authors.affiliation: †The School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.
authors.forename: Yue
authors.initials: Y
authors.lastname: Lin
authors.affiliation: †The School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.
authors.forename: Colin
authors.initials: C
authors.lastname: Norman
authors.affiliation: †The School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.
authors.forename: Deepanshu
authors.initials: D
authors.lastname: Srivastava
authors.affiliation: †The School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.
authors.forename: Feridoon
authors.initials: F
authors.lastname: Azough
authors.affiliation: †The School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: ‡European Thermodynamics Ltd, 8 Priory Business Park, Kibworth, Leicester LE8 0RX, United Kingdom.
authors.forename: Mark
authors.initials: M
authors.lastname: Robbins
authors.affiliation: ‡European Thermodynamics Ltd, 8 Priory Business Park, Kibworth, Leicester LE8 0RX, United Kingdom.
authors.forename: Kevin
authors.initials: K
authors.lastname: Simpson
authors.affiliation: †The School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.
authors.forename: Robert
authors.initials: R
authors.lastname: Freer
authors.affiliation: †The School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Kinloch
keywords: broad thermal window; bulk strontium titanate; environmental friendly; graphene; high thermoelectric performance