MnO 2 was prepared by column method from normal spinel LiMn 2O 4 with purity of 99.38%.The influence of LiMn 2O 4 grain size and acidity of leaching solution on the lithium leaching process was studied.The result...MnO 2 was prepared by column method from normal spinel LiMn 2O 4 with purity of 99.38%.The influence of LiMn 2O 4 grain size and acidity of leaching solution on the lithium leaching process was studied.The results show that the appropriate range of LiMn 2O 4 grain size was 60-160 meshes and the concentration of leaching solution HCl was 0.1 mol·L -1.The adsorption capacity Q of λ-MnO 2 for lithium increased with the increase of pH and changed markedly at pH 6.0-10.0.It was 3.80mmol/g at pH 12.0.The distribution coefficients K d of Li + and Na + were 3.406×10 4 and 2.300 respectively,and the separation coefficient α Li Na was 1.481×10 4 at pH 6.5.As a result,λ-MnO 2 is a high performance ion-sieve material for lithium ion.展开更多
A special method based on the local equilibrium principle has been introduced in the research of the phase diagram of Mn-MnO system.With this method,the problems of volatilization of Mn and the corrosion of Mn and MnO...A special method based on the local equilibrium principle has been introduced in the research of the phase diagram of Mn-MnO system.With this method,the problems of volatilization of Mn and the corrosion of Mn and MnO to refractory materials were prevented efficiently.The solubility of oxygen in Mn and the composition of the interface between MnO and Mn were determined.Partial phase diagram of Mn-MnO system were constructed according to pres- ent experimental results.展开更多
以氯化胆碱-乙二醇低共熔溶剂为反应介质,采用沉淀法制备了锂离子电池负极材料一氧化锰/碳多孔微球,并用X射线衍射(XRD)、扫描电镜(SEM)、比表面积及孔径分析、恒电流充放电技术、电化学阻抗谱和循环伏安等手段,研究了碳酸氢铵与氯化锰...以氯化胆碱-乙二醇低共熔溶剂为反应介质,采用沉淀法制备了锂离子电池负极材料一氧化锰/碳多孔微球,并用X射线衍射(XRD)、扫描电镜(SEM)、比表面积及孔径分析、恒电流充放电技术、电化学阻抗谱和循环伏安等手段,研究了碳酸氢铵与氯化锰物质的量比对一氧化锰/碳材料的形貌、结构及电化学性能的影响。结果表明,一氧化锰/碳材料的比表面积、孔径、孔体积、比容量、循环性能和倍率性能均随着碳酸氢铵与氯化锰物质的量比的增加而先增大后减小,碳酸氢铵与氯化锰物质的量比为2.0∶1时制备的一氧化锰/碳材料为多孔球体颗粒,粒径为0.5~2.5μm、平均孔径为11.5 nm、比表面积高达127.7 m2/g。一氧化锰/碳多孔微球材料在1C测试条件下的放电比容量为830 m A·h/g,循环50次后容量保持率接近100%,具有较高的比容量和较好的循环性能。展开更多
Normal spinel LiMn 2O 4 was synthesized by sol-gel method using lithium nitrate,manganese nitrate,citric acid and ethylene glycol as raw materials. LiMn 2O 4 was characterized by XRD,TG-DTA,IR,SEM and AAS.The opti...Normal spinel LiMn 2O 4 was synthesized by sol-gel method using lithium nitrate,manganese nitrate,citric acid and ethylene glycol as raw materials. LiMn 2O 4 was characterized by XRD,TG-DTA,IR,SEM and AAS.The optimum conditions for the synthesis were explored.Citric acid and ethylene glycol were mixed with molar ratio of 0.25,and the mixture was esterified at 140℃ for 4 hours.Then lithium nitrate and manganese nitrate were added with molar ratio of 0.6. In the system,the total molar of cations was equal to that of citric acid. At last, reflux the system at 105℃ for 2 hours. Dried gel was fired at 600℃ for 8 hours. Particle diameters of raw product were about 100 nm mainly. Further research shows that lithium ion of LiMn 2O 4 is easy to be extracted,and normal spinel λ-MnO 2 can be obtained after lithium ion extraction.展开更多
基金theNationalNaturalScienceFoundationofChi na (No .5 9972 0 2 7)theNaturalScienceFoundationofHubeiProvince (No .2 0 0 2AB0 74) )
文摘MnO 2 was prepared by column method from normal spinel LiMn 2O 4 with purity of 99.38%.The influence of LiMn 2O 4 grain size and acidity of leaching solution on the lithium leaching process was studied.The results show that the appropriate range of LiMn 2O 4 grain size was 60-160 meshes and the concentration of leaching solution HCl was 0.1 mol·L -1.The adsorption capacity Q of λ-MnO 2 for lithium increased with the increase of pH and changed markedly at pH 6.0-10.0.It was 3.80mmol/g at pH 12.0.The distribution coefficients K d of Li + and Na + were 3.406×10 4 and 2.300 respectively,and the separation coefficient α Li Na was 1.481×10 4 at pH 6.5.As a result,λ-MnO 2 is a high performance ion-sieve material for lithium ion.
文摘A special method based on the local equilibrium principle has been introduced in the research of the phase diagram of Mn-MnO system.With this method,the problems of volatilization of Mn and the corrosion of Mn and MnO to refractory materials were prevented efficiently.The solubility of oxygen in Mn and the composition of the interface between MnO and Mn were determined.Partial phase diagram of Mn-MnO system were constructed according to pres- ent experimental results.
文摘以氯化胆碱-乙二醇低共熔溶剂为反应介质,采用沉淀法制备了锂离子电池负极材料一氧化锰/碳多孔微球,并用X射线衍射(XRD)、扫描电镜(SEM)、比表面积及孔径分析、恒电流充放电技术、电化学阻抗谱和循环伏安等手段,研究了碳酸氢铵与氯化锰物质的量比对一氧化锰/碳材料的形貌、结构及电化学性能的影响。结果表明,一氧化锰/碳材料的比表面积、孔径、孔体积、比容量、循环性能和倍率性能均随着碳酸氢铵与氯化锰物质的量比的增加而先增大后减小,碳酸氢铵与氯化锰物质的量比为2.0∶1时制备的一氧化锰/碳材料为多孔球体颗粒,粒径为0.5~2.5μm、平均孔径为11.5 nm、比表面积高达127.7 m2/g。一氧化锰/碳多孔微球材料在1C测试条件下的放电比容量为830 m A·h/g,循环50次后容量保持率接近100%,具有较高的比容量和较好的循环性能。
基金FundedbytheNationalNaturalScienceFoundationofChi na (No .5 9972 0 2 7)
文摘Normal spinel LiMn 2O 4 was synthesized by sol-gel method using lithium nitrate,manganese nitrate,citric acid and ethylene glycol as raw materials. LiMn 2O 4 was characterized by XRD,TG-DTA,IR,SEM and AAS.The optimum conditions for the synthesis were explored.Citric acid and ethylene glycol were mixed with molar ratio of 0.25,and the mixture was esterified at 140℃ for 4 hours.Then lithium nitrate and manganese nitrate were added with molar ratio of 0.6. In the system,the total molar of cations was equal to that of citric acid. At last, reflux the system at 105℃ for 2 hours. Dried gel was fired at 600℃ for 8 hours. Particle diameters of raw product were about 100 nm mainly. Further research shows that lithium ion of LiMn 2O 4 is easy to be extracted,and normal spinel λ-MnO 2 can be obtained after lithium ion extraction.
