Ozone Oxidation Of Beta-of Niooh Prepared By Its Physical And Chemical Properties

The battery's history and the development of nickel-based battery are briefly introduced in this thesis.And the structure and electrochemical properties of nickel oxyhydroxide are reviewed in detail. The thesis also provides a brief introduction about the preparation methods of nickel oxyhydroxide. According to the reported literature,Author selected ozonation process to prepare nickel oxyhydroxides.Firstly,the author put the nickel hydroxide bought in market into glass container maken up by self.Then,the author made ozone react with nickel hydroxide under magnetic stirring.After the reaction last for some time,the substance in glass container is the pattern that we get.After the sample was prepared,firstly,author study the effect of making technology on the performance of nickel oxyhydroxide electrode through single factor experiment. According to the result,a group of orthogonal test is arranged,and the range analysis is employed to distinguish the influence significance of factors included in this test. Both the experimental results and the range analysis show that technology No. 9, which is specified as graphite powder content 25%, cold press pressure 16 MPa,CMC concentration 0．8%,is the best one among all the technologies described in this paper for preparing nickel oxyhydroxide electrode with the best performance. The relative influence significance of the technology factors is cold press pressure > CMC concentration> graphite powder content. At last,in order to prevent dropping of active materials from electrodes, two pieces of Ni foam substrates were pressed around the electrode using a pressure of 16MPa.After the NiOOH electrode's preparation methods is mature,the connection between the capacity of sample and oxidation time was studied by author.According to the investigation,the capacity of sample increases along with the protract of oxidation time on the whole.From 2h to 10h,the capacity is proportional to oxidation time on the whole. However,from 10h to 14h,the extent of improvement is very large.It should because the water that the previous reaction maked can not expel from the container favourably and accumulate in the container, The water has an effect of humidification on ozone.The efficiency of oxidation improve greatly because the wet ozone's oxidizability is better than the dry ozone.The author study the NiOOH electrode's property of constant current discharge through the experiment of constant current discharge.A second plateau was observed at a lower potential during discharge. According to the experimental data,it is found that the percent of the second plateau will decrease along with the protract of ozone oxidation's time or the reduce of the discharge multiplying factor.It's provided of the approximate reasons of this resust in the paper.SEM micrographs reveals that the sample's mean size isl3μm, most of the granule are spheroid and their surface is rough.It should because the granule impact with the wall of container and so on.Moreover,there are some granule break up into crumb,it will affect it's packed density.And most of these crumb adhere to the other large granule ,it should because the sample rub with the wall of container and so on and produce static,as a result, these crumb is absorbed to the large granule.These problem will be solved if the reaction facility adopt fluid bed.The XRD patterns show that the sample is made ofβ-NiOOH andβ-Ni(OH)2 and theγ-NiOOH had not been found in the sample.The XPS patterns reveal that theγ-NiOOH had not been found in the sample also.And according to the data,the author get the oxidizability of the sample that had been oxidated for 14 hours.The oxidizability is about 77．4%. The specific capacity calculated is 226．0 mAh/g based on the data and the specific capacity measured in practice is 203．7 mAh/g.Although the electrode's preparation methods have room to improve still,but relative to the preparation methods mentioned in the reported literature[3,4,8,10] ,it has maken great progress.Cyclic Voltammetry test indicates that the sample has one oxidation peak at about 0．466V and one reduction peak at about 0．315V.The other phenomena were observed are as follows.The current of oxidation peak and reduction peak reduced ,then remained constant along with the increase of cycle number;The reduction peak potential rised,then reduced thereafter remained constant along with the increase of cycle number;The oxidation peak potential is at the same rule on the whole;△E value is around 0．15V mostly and has very small change.Therefore,the author drawed a conclusion that the NiOOH sample has stable crystal lattice and exhibits good cycle reversibility.