Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9F...Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9FzO4-z were examined by inductively coupled plasma （ICP） and potentiometric analysis, the effects of F-substitution contents on structure, morphology and electrochemical performance of spinel Lil.03Coo.loMnl.9004 were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. It is found that the Lix.03 Co0.10Mnl.9oFzOa_z samples display a single phase of cubic spinel structure. The lattice parameters increase with the increase of F content when z〈_0.10. However, the lattice parameters begin to decrease when F content continues to increase. The results show that an appropriate amount ofF substitution for O element with Li＋, Co3＋ improves discharge capacity and structure stability of the materials. The Lil.03Co0.10Mnl.90FoAsO3.s5 sample shows an initial discharge capacity of 111.0 mA.h/g and has capacity retention of 97.0% after 30 cycles at 0.2C.展开更多
The hydrothermal synthesis of single-crystallineβ-MnO2 nanorods and their chemical conversion into single-crystalline LiMn2O4 nanorods by a simple solid-state reaction were reported.This method has the advantages of ...The hydrothermal synthesis of single-crystallineβ-MnO2 nanorods and their chemical conversion into single-crystalline LiMn2O4 nanorods by a simple solid-state reaction were reported.This method has the advantages of producing pure,single-phase and crystalline nanorods.The LiMn2O4 nanorods have an diameter of about 300 nm.The discharge capacity and cyclic performance of the batteries were investigated.The LiMn2O4 nanorods show better cyclic performance with a capacity retention ratio of 86.2% after 100 cycles.Battery cyclic studies reveal that the prepared LiMn2O4 nanorods have high capacity with a first discharge capacity of 128.7 mA·h/g.展开更多
The present work investigates the influence of ambient temperature on the steady-state off-design thermodynamic performance of a chemical looping combustion(CLC) combined cycle.A sensitivity analysis of the CLC reacto...The present work investigates the influence of ambient temperature on the steady-state off-design thermodynamic performance of a chemical looping combustion(CLC) combined cycle.A sensitivity analysis of the CLC reactor system was conducted,which shows that the parameters that influence the temperatures of the CLC reactors most are the flow rate and temperature of air entering the air reactor.For the ambient temperature variation,three off-design control strategies have been assumed and compared:1) without any Inlet Guide Vane(IGV) control,2) IGV control to maintain air reactor temperature and 3) IGV control to maintain constant fuel reactor temperature,aside from fuel flow rate adjusting.Results indicate that,compared with the conventional combined cycle,due to the requirement of pressure balance at outlet of the two CLC reactors,CLC combined cycle shows completely different off-design thermodynamic characteristics regardless of the control strategy adopted.For the first control strategy,temperatures of the two CLC reactors both rise obviously as ambient temperature increases.IGV control adopted by the second and the third strategy has the effect to maintain one of the two reactors' temperatures at design condition when ambient temperature is above design point.Compare with the second strategy,the third would induce more severe decrease of efficiency and output power of the CLC combined cycle.展开更多
基金Project(2011GZ0131) supported by the Sichuan Province Key Technology Support Program,China
文摘Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9FzO4-z were examined by inductively coupled plasma （ICP） and potentiometric analysis, the effects of F-substitution contents on structure, morphology and electrochemical performance of spinel Lil.03Coo.loMnl.9004 were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. It is found that the Lix.03 Co0.10Mnl.9oFzOa_z samples display a single phase of cubic spinel structure. The lattice parameters increase with the increase of F content when z〈_0.10. However, the lattice parameters begin to decrease when F content continues to increase. The results show that an appropriate amount ofF substitution for O element with Li＋, Co3＋ improves discharge capacity and structure stability of the materials. The Lil.03Co0.10Mnl.90FoAsO3.s5 sample shows an initial discharge capacity of 111.0 mA.h/g and has capacity retention of 97.0% after 30 cycles at 0.2C.
基金Project(2008AA031205)supported by the National High-tech Research and Development Program of China
文摘The hydrothermal synthesis of single-crystallineβ-MnO2 nanorods and their chemical conversion into single-crystalline LiMn2O4 nanorods by a simple solid-state reaction were reported.This method has the advantages of producing pure,single-phase and crystalline nanorods.The LiMn2O4 nanorods have an diameter of about 300 nm.The discharge capacity and cyclic performance of the batteries were investigated.The LiMn2O4 nanorods show better cyclic performance with a capacity retention ratio of 86.2% after 100 cycles.Battery cyclic studies reveal that the prepared LiMn2O4 nanorods have high capacity with a first discharge capacity of 128.7 mA·h/g.
基金supported by the National High Technology R&D Project of China (No 2006AA05A109)the National Key Fundamental Research Program of China (No2007CB210102)
文摘The present work investigates the influence of ambient temperature on the steady-state off-design thermodynamic performance of a chemical looping combustion(CLC) combined cycle.A sensitivity analysis of the CLC reactor system was conducted,which shows that the parameters that influence the temperatures of the CLC reactors most are the flow rate and temperature of air entering the air reactor.For the ambient temperature variation,three off-design control strategies have been assumed and compared:1) without any Inlet Guide Vane(IGV) control,2) IGV control to maintain air reactor temperature and 3) IGV control to maintain constant fuel reactor temperature,aside from fuel flow rate adjusting.Results indicate that,compared with the conventional combined cycle,due to the requirement of pressure balance at outlet of the two CLC reactors,CLC combined cycle shows completely different off-design thermodynamic characteristics regardless of the control strategy adopted.For the first control strategy,temperatures of the two CLC reactors both rise obviously as ambient temperature increases.IGV control adopted by the second and the third strategy has the effect to maintain one of the two reactors' temperatures at design condition when ambient temperature is above design point.Compare with the second strategy,the third would induce more severe decrease of efficiency and output power of the CLC combined cycle.
