Preparation Of Spherical Micro-nano Nickel Hydroxide And High Purity Ferrous Oxalate Dihydrate By Complex Precipitation

The Ni-MH batteries and lithium ion batteries are widely used invarious kinds of mobile electronic products due to high energy density,excellent cycle performance, mature technology and good resistance tocharge-discharge performance. In recent years, people put forward higherdemand to the performance of the Ni-MH batteries and lithium ionbatteries with the development of electric vehicle and hybrid electricvehicle. The discharge capacity and service life of Ni-MH battery isaffected directly by nickel hydroxide positive material. The purity anddischarge performance of lithium iron phosphate are affected directly bythe precursor materials ferrous oxalate. Therefore, this paper discusses thesynthesis and electrochemical performance of nickel hydroxide and ferrous oxalate.Firstly, the spherical β-Ni(OH)2and doped spherical β-Ni(OH)2withmicro-nano structure were synthesized by a controlled complexprecipitation method. The optimal synthetic conditions and dopingamount were obtained and the structures and morphologies werecharacterized by means of XRD, FSEM and TG test. The electrochemicalproperties of pure and doping products were investigation through thegalvanostatic charge-discharge and cyclic voltammetric experiments. Theresults show that the co-doped1%Zn,5%Co product possesses superiordischarge properties and cyclic performance, it can offer high dischargespecific capacity of257mAh g-1and more than800cycles life at a superhigh charge-discharge rate of50C, and the charging time of the productis reduced to1.2min.On this basis, this paper puts forward a new atom-economiccomplexation method which used nickel foam, water and the oxygen inair as the raw material to assemble a nickel/oxygen battery in order toprepare micro-nano spherical nickel hydroxide. The experiment indicatedthat the discharge property of the nickel/oxygen battery is determined byadditive concentration, reaction temperature, the performance of anodeand cathode. The structure, morphology and electrochemical properties ofprepared nickel hydroxide were also characterized by variousmeasurements. Finally, high-purity ferrous oxalate dihydrate was prepared by acontrollable crystallization complexation precipitation method. Thestructure and morphology of ferrous oxalate were characterized by XRD,FSEM and TG test. The purity of ferrous oxalate was analyzed throughthe redox titration, spectrophotometry and ICP-MS, the results suggestthat the purity of ferrous oxalate can be as high as99.7%.