A spherical-like Ni_(0.6)Co_(0.2)Mn_(0.2)(OH)_2 precursor was tuned homogeneously to synthesize LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 as a cathode material for lithium-ion batteries.The effects of calcination temperature on t...A spherical-like Ni_(0.6)Co_(0.2)Mn_(0.2)(OH)_2 precursor was tuned homogeneously to synthesize LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 as a cathode material for lithium-ion batteries.The effects of calcination temperature on the crystal structure,morphology,and the electrochemical performance of the as-prepared LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 were investigated in detail.The as-prepared material was characterized by X-ray diffraction,scanning electron microscopy,laser particle size analysis,charge–discharge tests,and cyclic voltammetry measurements.The results show that the spherical-like LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 material obtained by calcination at 900°C displayed the most significant layered structure among samples calcined at various temperatures,with a particle size of approximately 10 μm.It delivered an initial discharge capacity of 189.2 m Ah×g^(-1) at 0.2C with a capacity retention of 94.0% after 100 cycles between 2.7 and 4.3 V.The as-prepared cathode material also exhibited good rate performance,with a discharge capacity of 119.6 m Ah×g^(-1) at 5C.Furthermore,within the cut-off voltage ranges from 2.7 to 4.3,4.4,and 4.5 V,the initial discharge capacities of the calcined samples were 170.7,180.9,and 192.8 m Ah×g^(-1),respectively,at a rate of 1C.The corresponding retentions were 86.8%,80.3%,and 74.4% after 200 cycles,respectively.展开更多
China’s manganese resources are usually associated with the valuable elements such as silver, lead, zinc, cobalt, nickel, scandium, etc which should be comprehensively recovered during the manganese beneficiation. A ...China’s manganese resources are usually associated with the valuable elements such as silver, lead, zinc, cobalt, nickel, scandium, etc which should be comprehensively recovered during the manganese beneficiation. A manganese ore from western China contains Mn 23.18%, Co 0.073%, Ni 0.21% and Sc 0.013%. The mineralogy composition of ore and the occurrence of associated elements of Sc, Co as well as Ni are studied in this paper. According to the results, the manganese minerals in this ore are mainly lithiophorite and a little secondary pyrolusite. The lithiophorite in this ore is rich in aluminum and actually it is the generic name for the multi-mineral aggregates mixed by silicon, aluminum and iron, which is quite different with the ordinary psilomelane. There is not any Sc, Ni or Co mineral in this ore and more than 98% of Sc, Ni and Ni exists in lithiophorite and pyrolusite. The distribution of Sc, Co and Ni in lithiophorite is further studied by EPMA and the results indicate that Sc and Co in lithiophorite is sparse and dispersed distribution while Ni usually distributes in the argillaceous lithiophorite and is local enrichment. Reduction-sulfuric acid leaching tests show that the dissolution of Sc and Co happens before lithiophorite dissolves; the dissolution rate of Sc and Co is almost the same, which is significantly higher than the dissolution rate of manganese. However, the dissolution rate of Ni is extremely low with the dissolution of manganse, which indicates that Ni is hard to dissolve and its dissolution rate obviously lags behind that of Mn, Sc and Co. The conclusion can be drawn that Sc and Co exist in the lithiophorite crystals as interface adsorption while Ni exists in the clay (kaolinite) mixed up with lithiophorite as interface adsorption. The conclusion indicates that Sc and Co can dissolve before the dissolution of manganese at a high dissolution rate in the hydrometallurgical process while Ni is also into the solution through desorption from the interface of clay but its dissolution rate is rather slow because of the insoluble nature of clay.展开更多
Layered LiNi1/3Co1/3Mn1/3O2 materials were synthesized using a nickel-cobalt-manganese carbonate precursor obtained by chemical co-precipitation. The [Ni1/3Co1/3Mn1/3]CO3 precursor and the LiNi1/3Co1/3Mn1/3O2 powders ...Layered LiNi1/3Co1/3Mn1/3O2 materials were synthesized using a nickel-cobalt-manganese carbonate precursor obtained by chemical co-precipitation. The [Ni1/3Co1/3Mn1/3]CO3 precursor and the LiNi1/3Co1/3Mn1/3O2 powders were characterized by X-ray diffraction（XRD） and scanning electron micrograph（SEM）. The SEM analysis shows that these particles possess uniform and spherical morphology. The electrochemical properties of the (LiNi1/3-)(Co1/3Mn1/3O2) cathode material for rechargeable lithium-ion batteries such as the galvanostatic charge-discharge performance and cyclic voltammetry（CV） were measured. The results show that an initial discharge capacity of 190.29mA·h·g-1 is obtained in the voltage range of 2.54.6V and at a current rate of 0.1C at 25℃.The discharge capacity increases linearly with the increase of the upper cut-off voltage limit.展开更多
Gas generation induced by parasitic reactions in lithium-metal batteries(LMB)has been regarded as one of the fundamental barriers to the reversibility of this battery chemistry,which occurs via the complex interplays ...Gas generation induced by parasitic reactions in lithium-metal batteries(LMB)has been regarded as one of the fundamental barriers to the reversibility of this battery chemistry,which occurs via the complex interplays among electrolytes,cathode,anode,and the decomposition species that travel across the cell.In this work,a novel in situ differential electrochemical mass spectrometry is constructed to differentiate the speciation and source of each gas product generated either during cycling or during storage in the presence of cathode chemistries of varying structure and nickel contents.It unambiguously excludes the trace moisture in electrolyte as the major source of hydrogen and convincingly identifies the layer-structured NCM cathode material as the source of instability that releases active oxygen from the lattice at high voltages when NCM experiences H2→H3 phase transition,which in turn reacts with carbonate solvents,producing both CO_(2)and proton at the cathode side.Such proton in solvated state travels across the cell and becomes the main source for hydrogen generated at the anode side.Mechanisms are proposed to account for these irreversible reactions,and two electrolyte additives based on phosphate structure are adopted to mitigate the gas generation based on the understanding of the above decomposition chemistries.展开更多
基金financially supported by NSAF(No.U1530155)Ministry of Science and Technology(MOST)of China,US–China Collaboration on Cutting-edge Technology Development of Electric Vehicle,the Nation Key Basic Research Program of China(No.2015CB251100)Beijing Key Laboratory of Environmental Science and Engineering(No.20131039031)
文摘A spherical-like Ni_(0.6)Co_(0.2)Mn_(0.2)(OH)_2 precursor was tuned homogeneously to synthesize LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 as a cathode material for lithium-ion batteries.The effects of calcination temperature on the crystal structure,morphology,and the electrochemical performance of the as-prepared LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 were investigated in detail.The as-prepared material was characterized by X-ray diffraction,scanning electron microscopy,laser particle size analysis,charge–discharge tests,and cyclic voltammetry measurements.The results show that the spherical-like LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 material obtained by calcination at 900°C displayed the most significant layered structure among samples calcined at various temperatures,with a particle size of approximately 10 μm.It delivered an initial discharge capacity of 189.2 m Ah×g^(-1) at 0.2C with a capacity retention of 94.0% after 100 cycles between 2.7 and 4.3 V.The as-prepared cathode material also exhibited good rate performance,with a discharge capacity of 119.6 m Ah×g^(-1) at 5C.Furthermore,within the cut-off voltage ranges from 2.7 to 4.3,4.4,and 4.5 V,the initial discharge capacities of the calcined samples were 170.7,180.9,and 192.8 m Ah×g^(-1),respectively,at a rate of 1C.The corresponding retentions were 86.8%,80.3%,and 74.4% after 200 cycles,respectively.
文摘China’s manganese resources are usually associated with the valuable elements such as silver, lead, zinc, cobalt, nickel, scandium, etc which should be comprehensively recovered during the manganese beneficiation. A manganese ore from western China contains Mn 23.18%, Co 0.073%, Ni 0.21% and Sc 0.013%. The mineralogy composition of ore and the occurrence of associated elements of Sc, Co as well as Ni are studied in this paper. According to the results, the manganese minerals in this ore are mainly lithiophorite and a little secondary pyrolusite. The lithiophorite in this ore is rich in aluminum and actually it is the generic name for the multi-mineral aggregates mixed by silicon, aluminum and iron, which is quite different with the ordinary psilomelane. There is not any Sc, Ni or Co mineral in this ore and more than 98% of Sc, Ni and Ni exists in lithiophorite and pyrolusite. The distribution of Sc, Co and Ni in lithiophorite is further studied by EPMA and the results indicate that Sc and Co in lithiophorite is sparse and dispersed distribution while Ni usually distributes in the argillaceous lithiophorite and is local enrichment. Reduction-sulfuric acid leaching tests show that the dissolution of Sc and Co happens before lithiophorite dissolves; the dissolution rate of Sc and Co is almost the same, which is significantly higher than the dissolution rate of manganese. However, the dissolution rate of Ni is extremely low with the dissolution of manganse, which indicates that Ni is hard to dissolve and its dissolution rate obviously lags behind that of Mn, Sc and Co. The conclusion can be drawn that Sc and Co exist in the lithiophorite crystals as interface adsorption while Ni exists in the clay (kaolinite) mixed up with lithiophorite as interface adsorption. The conclusion indicates that Sc and Co can dissolve before the dissolution of manganese at a high dissolution rate in the hydrometallurgical process while Ni is also into the solution through desorption from the interface of clay but its dissolution rate is rather slow because of the insoluble nature of clay.
基金supported by the National Natural Science Foundation of China (No. U2033204)Engineering Laboratory of Battery Safety and Accident Control of Petroleum and Chemical Industry, China (No. ELBSAC202304)supported by Youth Innovation Promotion Association, Chinese Academy of Sciences (No. Y201768)
文摘Layered LiNi1/3Co1/3Mn1/3O2 materials were synthesized using a nickel-cobalt-manganese carbonate precursor obtained by chemical co-precipitation. The [Ni1/3Co1/3Mn1/3]CO3 precursor and the LiNi1/3Co1/3Mn1/3O2 powders were characterized by X-ray diffraction（XRD） and scanning electron micrograph（SEM）. The SEM analysis shows that these particles possess uniform and spherical morphology. The electrochemical properties of the (LiNi1/3-)(Co1/3Mn1/3O2) cathode material for rechargeable lithium-ion batteries such as the galvanostatic charge-discharge performance and cyclic voltammetry（CV） were measured. The results show that an initial discharge capacity of 190.29mA·h·g-1 is obtained in the voltage range of 2.54.6V and at a current rate of 0.1C at 25℃.The discharge capacity increases linearly with the increase of the upper cut-off voltage limit.
基金the financial supports from the Key-Area Research and Development Program of Guangdong Province(2020B090919001)Shenzhen Key Laboratory of Solid-State Batteries(ZDSYS20180208184346531)+1 种基金Guangdong Provincial Key Laboratory of Energy Materials for Electric Power(2018B030322001)Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices(2019B121205001)。
文摘Gas generation induced by parasitic reactions in lithium-metal batteries(LMB)has been regarded as one of the fundamental barriers to the reversibility of this battery chemistry,which occurs via the complex interplays among electrolytes,cathode,anode,and the decomposition species that travel across the cell.In this work,a novel in situ differential electrochemical mass spectrometry is constructed to differentiate the speciation and source of each gas product generated either during cycling or during storage in the presence of cathode chemistries of varying structure and nickel contents.It unambiguously excludes the trace moisture in electrolyte as the major source of hydrogen and convincingly identifies the layer-structured NCM cathode material as the source of instability that releases active oxygen from the lattice at high voltages when NCM experiences H2→H3 phase transition,which in turn reacts with carbonate solvents,producing both CO_(2)and proton at the cathode side.Such proton in solvated state travels across the cell and becomes the main source for hydrogen generated at the anode side.Mechanisms are proposed to account for these irreversible reactions,and two electrolyte additives based on phosphate structure are adopted to mitigate the gas generation based on the understanding of the above decomposition chemistries.
