新能源材料与技术Renewable Energy: Materials and TechnologiesL5: Energy Storage and Batteries (II)DrYiminChaoy.chao@uea.ac.ukwww.uea.ac.uk/chemistry/people/faculty/chao
新能源材料与技术 Renewable Energy: Materials and Technologies L5: Energy Storage and Batteries (II) Dr Yimin Chao y.chao@uea.ac.uk www.uea.ac.uk/chemistry/people/faculty/chao
Backtofundamentals·lmprovedcyclelifeof newest lead-acidbatteriesvariants·Otherweaknessoflead-acidbatteryremainsLowspecificenergyReduceweight-4o%inseparators,electrolyteandcaseElectrolyte involved in electrode chemistrydoesn't contribute to energyIntrinsicchemistryproblemsOnly2 Vpotential, doubling as in Li batteries doubles specific energy
Back to fundamentals •Improved cycle life of newest lead-acid ba:eries variants •Other weakness of lead-acid ba:ery remains Low specific energy Reduce weight – 40% in separators, electrolyte and case Electrolyte involved in electrode chemistry, doesn’t contribute to energy Intrinsic chemistry problems Only 2 V potenBal, doubling as in Li baDeries doubles specific energy
Simplest battery designSeparatorCurrentcollectorCurrentcollectorCathodeAnodeMustconsidercapacityofbothcomponents
Anode Cathode Current collector Current collector Separator Must consider capacity of both components Simplest ba:ery design
Li-ion batteries
Li-ion ba:eries
Li-ion batteriesBasedonthehalfcellreactionLi(s) = Li++ eWhylithium?Most electropositive element, E°= -3.04 V, light element, AW = 6.94 g mol-1TwoaspectsStorage of Li (anode)Storage of Li+(cathode)Associatedhalf cell reaction depending on the material used
Based on the half cell reacDon Li(s) = Li++ e Why lithium? Most electroposiDve element, E°= -3.04 V, light element, AW = 6.94 g mol-1 Two aspects Storage of Li (anode) Storage of Li+(cathode) Associated half cell reacBon depending on the material used Li-ion ba:eries
Materials useoCathodeactivematerialsinCarbonforLIBanodesbytype(2011)2011:63000TonsMCMBArtificialLiFePO_8%LiMn,OLFPGraphiteAmorphousLMO30%8%2%11%LiCoO2LSiorSnNaturalLCOTypeNCAGraphite1%43%59%6%Li[NiCoAl]O2NMC32%Li[NiMnCo]O2
Materials used LiCoO2 LiMn2O4 LiFePO4 Li[NiMnCo]O2 Li[NiCoAl]O2
Storage of LiLitmustdiffusetowardscathodeArtificialLight element, AW = 6.94 g mol-1Li,P/Li,NE°=-3.04VMostelectropositiveelement,Solid-stateReactivetowards airand water(especiallyLiLi-ionwhendispersed)conductorTechnicalchallengestopure LianodeSpontaneousReactionswithelectrolyteLi,co,AproticelectrolyteLi,oInvestigated as part of Li-airbatteryLiLiOHXsolidelectrolyte interphase (SEl)http://en.wikipedia.org/wiki/File:Li-air-SEl.jpg
Storage of Li Light element, AW = 6.94 g mol-1 Most electroposiDve element, E°= -3.04 V ReacDve towards air and water (especially when dispersed) Technical challenges to pure Li anode ReacDons with electrolyte InvesDgated as part of Li-air ba:ery Li+ must diffuse towards cathode h:p://en.wikipedia.org/wiki/File:Li-air-SEI.jpg solid electrolyte interphase (SEI)
Storage of LiIntercalationcompoundsTransitionmetal chalcogenidesTis,Li,Tis,CarbonMetal alloysSn, SiConversionreactionMetaloxide (CoO,Nio, CuOorFeO)
Storage of Li IntercalaDon compounds TransiDon metal chalcogenides TiS2 LixTiS2 Carbon Metal alloys Sn, Si Conversion reacDon Metal oxide (CoO, NiO, CuO or FeO)
Storageof Li-intercalation compoundsLiCeGraphiticcarbonCo + xLi = xLiC62.34(3) A7.40(5)A3.64(5) GoldenyellowStaging,expansiononly5.17(5)AReduction inspecificenergyLiCg,MW=78.94,372mAh/gReadilyavailableCheapDecomposesabove100°℃1.42(2)AONLYcommercialanode4.30(5) A2.86(2) A 2.47(3) A
Storage of Li – intercalaDon compounds C6 + xLi = xLiC6 Golden yellow Staging, expansion only ReducDon in specific energy LiC6, MW = 78.94, 372 mAh/g Readily available Cheap Decomposes above 100°C ONLY commercial anode
Diffusion of LiLimustdiffusebetweenlaversincharging and discharging~10llcm2slOftheorder2Dt1 hour, 2-600 μm~10-6cm2s-Typicalused,10-20umNanochannels,microporesOxidationtoremovereactivesitesK.Persson,V.A.Sethuraman, L.J.Hardwick, Y.Hinuma, Y.S.MengA. van der Ven, V.Srinivasan, R.Kostecki, G. Ceder. J. Phys.Chem.Lett.2010,1,1176-1180
Diffusion of Li Li must diffuse between layers in charging and discharging Of the order 1 hour, 2-600 µm Typical used, 10-20 µm Nanochannels, micropores OxidaDon to remove reacDve sites K. Persson, V.A. Sethuraman, L.J. Hardwick, Y. Hinuma, Y.S. Meng, A. van der Ven, V. Srinivasan, R. Kostecki, G. Ceder. J. Phys. Chem. LeD. 2010, 1, 1176-1180. 2D t