The standard molar formation enthalpies of （A＋）2Cd2（SO4）3[A＋is NH-4＋or K＋ ] are determined from the enthalpies of dissolution （ΔSHm） of [（A＋）2SO4（s）＋ 2CdSO4（s）] and （A＋ ）2Cd2（SO4）3（s） in twic...The standard molar formation enthalpies of （A＋）2Cd2（SO4）3[A＋is NH-4＋or K＋ ] are determined from the enthalpies of dissolution （ΔSHm） of [（A＋）2SO4（s）＋ 2CdSO4（s）] and （A＋ ）2Cd2（SO4）3（s） in twice distilled water or 3 mol· L－ 1 HNO3 solvent respectively,at 298.2 K,as: Δ fHm[（NH4）2Cd2（SO4）3,s,298.2K]=－ 3031.74± 0.08 kJ· mol－1 Δ fHm[K2Cd2（SO4）3,s,298.2K]=－ 3305.52± 0.17 kJ·展开更多
为了获得电化学性能优良的锂离子薄膜电池正极材料,采用快速退火技术制备L iMn2O4薄膜,用X射线衍射、扫描电子显微镜检测和分析了薄膜的物相及表面形貌;用循环伏安、恒流充放电研究了L iMn2O4薄膜的电化学性质。结果表明,制备的L iMn2O...为了获得电化学性能优良的锂离子薄膜电池正极材料,采用快速退火技术制备L iMn2O4薄膜,用X射线衍射、扫描电子显微镜检测和分析了薄膜的物相及表面形貌;用循环伏安、恒流充放电研究了L iMn2O4薄膜的电化学性质。结果表明,制备的L iMn2O4薄膜均匀、致密、无龟裂;在退火温度从700℃升高到850℃的过程中,薄膜容量从34μAh/(cm2.μm)逐步升高到40μAh/(cm2.μm);当退火时间从1 m in延长到4 m in时,薄膜容量由36μAh/(cm2.μm)升高到41μAh/(cm2.μm),但当退火时间进一步延长到8 m in时,薄膜容量下降到39.5μAh/(cm2.μm);对于不同温度退火2 m in制备的薄膜而言,800℃退火得到的L iMn2O4薄膜经100次循环后的每次容量损失为0.021%,循环性能最好;对于750℃不同退火时间制备的L iMn2O4薄膜来说,退火时间为4 m in时得到的薄膜循环性能最好,经100次循环后每次容量损失仅为0.025%,表明快速退火制备的L iMn2O4薄膜具有优良的循环性能。展开更多
The standard enthalpy of formation ( Δ \-f H\+\+ \-\-m[K\-2Zn(IO\-3)\-4·2H\-2O,s,298.2K]=-2210.68 kJ·mol\+\{-1\}) of a double salt K\-2Zn(IO\-3)\-4·2H\-2O is determined by solution calorimetry in a i...The standard enthalpy of formation ( Δ \-f H\+\+ \-\-m[K\-2Zn(IO\-3)\-4·2H\-2O,s,298.2K]=-2210.68 kJ·mol\+\{-1\}) of a double salt K\-2Zn(IO\-3)\-4·2H\-2O is determined by solution calorimetry in a isoperibel reaction calorimeter. The calorimetric solvent is an acid solution consisting of 3 mol·L\+\{-1\} HNO\-3. Accoding to the HESS Law, we designed a rational thermochemical cycle. Simultaneously, the Δ \-f H\+\+ \-\-\{m 298.2K\} was calculated from the data of the DSC curve. The values obtained by the two methods were compared.展开更多
文摘The standard molar formation enthalpies of （A＋）2Cd2（SO4）3[A＋is NH-4＋or K＋ ] are determined from the enthalpies of dissolution （ΔSHm） of [（A＋）2SO4（s）＋ 2CdSO4（s）] and （A＋ ）2Cd2（SO4）3（s） in twice distilled water or 3 mol· L－ 1 HNO3 solvent respectively,at 298.2 K,as: Δ fHm[（NH4）2Cd2（SO4）3,s,298.2K]=－ 3031.74± 0.08 kJ· mol－1 Δ fHm[K2Cd2（SO4）3,s,298.2K]=－ 3305.52± 0.17 kJ·
文摘为了获得电化学性能优良的锂离子薄膜电池正极材料,采用快速退火技术制备L iMn2O4薄膜,用X射线衍射、扫描电子显微镜检测和分析了薄膜的物相及表面形貌;用循环伏安、恒流充放电研究了L iMn2O4薄膜的电化学性质。结果表明,制备的L iMn2O4薄膜均匀、致密、无龟裂;在退火温度从700℃升高到850℃的过程中,薄膜容量从34μAh/(cm2.μm)逐步升高到40μAh/(cm2.μm);当退火时间从1 m in延长到4 m in时,薄膜容量由36μAh/(cm2.μm)升高到41μAh/(cm2.μm),但当退火时间进一步延长到8 m in时,薄膜容量下降到39.5μAh/(cm2.μm);对于不同温度退火2 m in制备的薄膜而言,800℃退火得到的L iMn2O4薄膜经100次循环后的每次容量损失为0.021%,循环性能最好;对于750℃不同退火时间制备的L iMn2O4薄膜来说,退火时间为4 m in时得到的薄膜循环性能最好,经100次循环后每次容量损失仅为0.025%,表明快速退火制备的L iMn2O4薄膜具有优良的循环性能。
文摘The standard enthalpy of formation ( Δ \-f H\+\+ \-\-m[K\-2Zn(IO\-3)\-4·2H\-2O,s,298.2K]=-2210.68 kJ·mol\+\{-1\}) of a double salt K\-2Zn(IO\-3)\-4·2H\-2O is determined by solution calorimetry in a isoperibel reaction calorimeter. The calorimetric solvent is an acid solution consisting of 3 mol·L\+\{-1\} HNO\-3. Accoding to the HESS Law, we designed a rational thermochemical cycle. Simultaneously, the Δ \-f H\+\+ \-\-\{m 298.2K\} was calculated from the data of the DSC curve. The values obtained by the two methods were compared.
