The Preparation Of Bismuth Oxychloride And Bismuth Molybdate And Studies For Their Electrochemical Performance

Since the 21st century,with the intensification of global pollution,increasing energy demand,and the development of electronic vehicles and portable electronic devices,the exploration of alkaline secondary batteries and lithium ion batteries is of great significance to society development.In this paper,the {110} and {001} crystal facet exposed BiOCl samples were synthesized respectively as electrode materials in alkaline secondary batteries and lithium ion batteries.Secondly,three bismuth molybdate samples with different crystal phases were synthesized as electrode materials in lithium ion battery.The electrochemical properties of these electrode materials were studied.The main contents of this paper are as follows:1.With bismuth nitrate and potassium chloride as raw material,two kinds of BiOCl materials with different {001} and {110} exposed facet were synthesized through the hydrolysis method at room temperature,respectively.The exposed facet of two samples are confirmed by X-ray diffraction(XRD)and transmission electron microscopy(TEM),and the nanosheet morphology of two samples are confirmed by scanning electron microscopy(SEM).The electrochemical properties of two samples in Ni/Bi alkaline secondary batteries are studied with the Ni(OH)2 cathode as counter electrode.The result of electrochemical tests shows that the BiOCl electrode material with the {110} exposed facet exhibited a specific capacity of 213.4 mAh g-1 at the current density of 0.5 A g-1.When the current density was up to 5 A g-1,the specific capacity of sample still remains at 162.5 mAh g-1.Also,73%of initial capacity was kept after 500 cycles at 2 A g-1.These results reveal that the BiOCl electrode with the{110} exposed facet shows better electrochemical performance compared to the BiOCl electrode with the ?001} exposed facet.2.The electrochemical performance of the prepared BiOCl electrode materials with {001} and {110} exposed facet in Li ion batteries are studied using lithium metal as counter electrode.The results showed that the BiOCl sample with the {110}exposed facet performed an advanced reversible capacity and rate capability compared to the samplel with the {001} exposed facet.It may be due to the {110}exposed facet provides more active site and shortens the Li ion migration channels for the Li ion intercalation/deintercalation reaction.3.With bismuth nitrate and sodium molybdate as raw materials,three kinds of bismuth molybdate materials with different crystal phases(a-Bi2Mo3O12,P-Bi2MO2O9 and y-Bi2MoO6)are prepared by hydrothermal method.The electrochemical performance of the prepared samples in Li ion batteries are studied using lithium metal as counter electrode.The result shows that all those candidates show a promising electrochemical activity in Li ion battery,with a stable discharge platform at 0.7 V,which proved that all those bismuth molybdate samples can be potential anode materials in Li ion battery.The y-Bi2MoO6 sample exhibited the better electrochemical performance with the higher reversible capacity and rate capability due to the layer structure of y-Bi2MoO6 that can provide more ion channels for the Li ion intercalation/deintercalation reaction.