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Hard carbon derived from cellulose as anode for sodium ion batteries:Dependence of electrochemical properties on structure 被引量:20
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作者 v.simone A.Boulineau +3 位作者 A.de Geyer D.Rouchon L.simonin S.Martinet 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第5期761-768,共8页
Cellulose, the most abundant organic polymer on Earth, is a sustainable source of carbon to use as a negative electrode for sodium ion batteries. Here, hard carbons(HC) prepared by cellulose pyrolysis were investigate... Cellulose, the most abundant organic polymer on Earth, is a sustainable source of carbon to use as a negative electrode for sodium ion batteries. Here, hard carbons(HC) prepared by cellulose pyrolysis were investigated with varying pyrolysis temperature from 700 °C to 1600 °C. Characterisation methods such as Small Angle X-ray Scattering(SAXS) measurements and N2adsorption were performed to analyse porosity differences between the samples. The graphene sheet arrangements were observed by transmission electron microscopy(TEM): an ordering of the graphene sheets is observed at temperatures above 1150 °C and small crystalline domains appear over 1400 °C. As the graphene sheets start to align, the BET surface area decreases and the micropore size increases. To correlate hard carbon structures and electrochemical performances, different tests in Na//HC cells with 1 M NaPF6ethylene carbonate/dimethyl carbonate(EC/DMC) were performed. Samples pyrolysed from 1300 °C to 1600 °C showed a 300 m Ah/g reversible capacity at C/10 rate(where C = 372 mA/g) with an excellent stability in cycling and a very good initial Coulombic efficiency of up to 84%. Furthermore, hard carbons showed an excellent rate capability where sodium extraction rate varies from C/10 to 5C. At 5C more than 80% of reversible capacity remains stable for hard carbons synthesized from 1000 °C to 1600 °C. 展开更多
关键词 Sodium ion battery ANODE Hard carbon STRUCTURE
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Structural and Magnetic Properties of MnO-P_2O_5-PbO Glasses
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作者 I.Ardelean M.Peteanu +2 位作者 O.Cozar v.simon v.Mih and G.Botezan (Faculty of Physics, Babes-Bolyai University, 3400 Cluj-Napoca, Romania To whom correspondence should be addressedE-mail: arde@phys.ubbcluj.ro ) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第5期453-456,共4页
The xMnO(100-x)[2P2O5.PbO] glasses were prepared with MnO concentration being in the range of 0≤x≤50 mole fraction and were investigated by EPR spectroscopy and magneticsusceptibility measurements. Octahedral symmet... The xMnO(100-x)[2P2O5.PbO] glasses were prepared with MnO concentration being in the range of 0≤x≤50 mole fraction and were investigated by EPR spectroscopy and magneticsusceptibility measurements. Octahedral symmetric sites tetragonally distorted were detected for x≤5 mole fraction MnO. Only Mn2+ ions were identified in these glasses, involved in dipoledipole interactions 展开更多
关键词 PBO MNO Structural and Magnetic Properties of MnO-P2O5-PbO Glasses
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EPR and Magnetic Susceptibility Investigations of Fe Containing TeO_2-B_2O_3-SrF_2 Glasses
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作者 I.Ardelean, M.Peteanut, v.simon and F.Ciorcas (Faculty of Physics, Babes-Bolyai University, 3400 Cluj-Napoca, Romania) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第6期596-600,共5页
Iron ions were used as probes to explore the structural and magnetic properties of 70TeO2'25B2O3' 5SrF2 vitreous matrix. The distribution of Fe3+ ions on different structural aggregates was revealed by means ... Iron ions were used as probes to explore the structural and magnetic properties of 70TeO2'25B2O3' 5SrF2 vitreous matrix. The distribution of Fe3+ ions on different structural aggregates was revealed by means of EPR, as depending on Fe2O3 concentration. Strongly distorted octahedral sites were detected for the isolated paramagnetic ions, and also clusters of Fe ions especially at high Fe2O3 content of samples. Magnetic susceptibility measurements evidenced both dipoledipole and superexchange type interactions involving iron ions. Mixed valence states of iron ions were also detected 展开更多
关键词 Te In FE EPR and Magnetic Susceptibility Investigations of Fe Containing TeO2-B2O3-SrF2 Glasses line
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冲动式?反动式?可变式!最高效率的新一代汽轮机通流部分
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作者 v.simon 吴迎曦 《东方汽轮机》 2001年第3期86-93,共8页
关键词 冲动式 反动式 可变式 汽轮机 通流部分
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