In this paper, we report a new kind of moist chemical method for preparing LiNiVO 4 which can be used to prepare lithium ion battery for the cathode active materials with a very high battery voltage(48 V vs. Li). Li 2...In this paper, we report a new kind of moist chemical method for preparing LiNiVO 4 which can be used to prepare lithium ion battery for the cathode active materials with a very high battery voltage(48 V vs. Li). Li 2CO 3, NiCO 3 and NH 4VO 3 were used as row materials, and H 2C 2O 4 saturated solution was used both as a precipitate agent and as a complex agent. The precursor gel composed of (NH 4) 2(VO) 2(C 2O 4) 4·6H 2O, NiC 2O 4·2H 2O and Li 2C 2O 4 can be obtained, and after sintering the dry gel we got the products. The results of XRD show that the product sintered at 400 ℃ for 2 h exists in a cubic crystal, single phase, inverse LiNiVO 4 and the average sizes (by Scherrer formula ) were 40—50 nm(400 ℃, 2 h ) and 65—70 nm(700 ℃, 2 h) , respectively, a=0.822 3(1) nm. The TG and DTA curves implied that the dry gel underwent water loss, decompositions of oxalates and complex oxalate, the solid state reactions finished at 377 ℃. The results of XPS proved that the valence in LiNiVO 4 would be Li+,V 5+ , Ni 2+ (in the main), respectively. From ICP analysis we also knew that the sample corresponded basically to stoichiometry LiNiVO 4 .展开更多
Porous LiNiVO4 powder was synthesized via solution combustion synthesis method using lithium nitrate, nickel nitrate,ammonium metavanadate and citric acid as raw materials. Thermogravimetry (TG) and differential scann...Porous LiNiVO4 powder was synthesized via solution combustion synthesis method using lithium nitrate, nickel nitrate,ammonium metavanadate and citric acid as raw materials. Thermogravimetry (TG) and differential scanning calorimetry (DSC),X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM) were used toevaluate the structures and morphologies of samples. The results show that the calcination temperature has significant effect on thecrystallinity and morphologies. Pure LiNiVO4 flaky nanoparticles with a mean particle size around 20 nm can be readily prepared bycalcining the precursor in air at 500 °C for 2 h. As a cathode material for lithium-ion batteries, the porous LiNiVO4 powder exhibits agood structural reversibility.展开更多
The single phase LiNiVO4 has been successfully synthesized by adopting a new mild liquid route with oxalic acid as both complexant and precipitant, and this method is named the CPG method. The products were obtained b...The single phase LiNiVO4 has been successfully synthesized by adopting a new mild liquid route with oxalic acid as both complexant and precipitant, and this method is named the CPG method. The products were obtained by sintering the dry gel precursor which was prepared by the CPG method at 200-850°C for 2-10 h in air. The products were tested by XRD, XPS, ESR and TGA-DTA, and the results indicate that the single phase LiNiVO4 could be obtained at 450°C for 2-3 h in air and LiNiVO4 was still steady at 850°C for 10 h. The valence analyses show that in LiNiVO4 the valence of lithium is +1, both nickel and vanadium have the mixed valence, namely +2, +3 for nickel and +4, +5 for vanadium respectively. The LiNiVO4 can be expressed as LiNi3+xNi2+1-xV4+xV5+1-xO4 (O≤x【1). The pyrolysis mechanism of the dry gel is also discussed.展开更多
1 Results Due to the high cell voltage of LiNiVO4,the compound properties have been continuously studied as the potential cathode material for Li-ion batteries.LiNiVO4 cathode product has been known to exhibit high ce...1 Results Due to the high cell voltage of LiNiVO4,the compound properties have been continuously studied as the potential cathode material for Li-ion batteries.LiNiVO4 cathode product has been known to exhibit high cell voltage of 4.8 V[1].LiCH3COO.2H2O (Sigma),Ni(CH3COO)2.4H2O (Aldrich) and NH4VO3(Ajax Finechem) were used as the starting reactants. In this work,LiNiVO4 was prepared by the sol gel method.This method was used to replace the conventional solid state reaction method in terms of the sample ...展开更多
文摘In this paper, we report a new kind of moist chemical method for preparing LiNiVO 4 which can be used to prepare lithium ion battery for the cathode active materials with a very high battery voltage(48 V vs. Li). Li 2CO 3, NiCO 3 and NH 4VO 3 were used as row materials, and H 2C 2O 4 saturated solution was used both as a precipitate agent and as a complex agent. The precursor gel composed of (NH 4) 2(VO) 2(C 2O 4) 4·6H 2O, NiC 2O 4·2H 2O and Li 2C 2O 4 can be obtained, and after sintering the dry gel we got the products. The results of XRD show that the product sintered at 400 ℃ for 2 h exists in a cubic crystal, single phase, inverse LiNiVO 4 and the average sizes (by Scherrer formula ) were 40—50 nm(400 ℃, 2 h ) and 65—70 nm(700 ℃, 2 h) , respectively, a=0.822 3(1) nm. The TG and DTA curves implied that the dry gel underwent water loss, decompositions of oxalates and complex oxalate, the solid state reactions finished at 377 ℃. The results of XPS proved that the valence in LiNiVO 4 would be Li+,V 5+ , Ni 2+ (in the main), respectively. From ICP analysis we also knew that the sample corresponded basically to stoichiometry LiNiVO 4 .
文摘Porous LiNiVO4 powder was synthesized via solution combustion synthesis method using lithium nitrate, nickel nitrate,ammonium metavanadate and citric acid as raw materials. Thermogravimetry (TG) and differential scanning calorimetry (DSC),X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM) were used toevaluate the structures and morphologies of samples. The results show that the calcination temperature has significant effect on thecrystallinity and morphologies. Pure LiNiVO4 flaky nanoparticles with a mean particle size around 20 nm can be readily prepared bycalcining the precursor in air at 500 °C for 2 h. As a cathode material for lithium-ion batteries, the porous LiNiVO4 powder exhibits agood structural reversibility.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29871021).
文摘The single phase LiNiVO4 has been successfully synthesized by adopting a new mild liquid route with oxalic acid as both complexant and precipitant, and this method is named the CPG method. The products were obtained by sintering the dry gel precursor which was prepared by the CPG method at 200-850°C for 2-10 h in air. The products were tested by XRD, XPS, ESR and TGA-DTA, and the results indicate that the single phase LiNiVO4 could be obtained at 450°C for 2-3 h in air and LiNiVO4 was still steady at 850°C for 10 h. The valence analyses show that in LiNiVO4 the valence of lithium is +1, both nickel and vanadium have the mixed valence, namely +2, +3 for nickel and +4, +5 for vanadium respectively. The LiNiVO4 can be expressed as LiNi3+xNi2+1-xV4+xV5+1-xO4 (O≤x【1). The pyrolysis mechanism of the dry gel is also discussed.
文摘1 Results Due to the high cell voltage of LiNiVO4,the compound properties have been continuously studied as the potential cathode material for Li-ion batteries.LiNiVO4 cathode product has been known to exhibit high cell voltage of 4.8 V[1].LiCH3COO.2H2O (Sigma),Ni(CH3COO)2.4H2O (Aldrich) and NH4VO3(Ajax Finechem) were used as the starting reactants. In this work,LiNiVO4 was prepared by the sol gel method.This method was used to replace the conventional solid state reaction method in terms of the sample ...
