The Preparation Of Copper-based LIB Anode Materials And Their Electrochemical Properties

LIBs are very potential electrical energy storage devices due to its high energy density and long cycle life,for electric cars and portable electronic products.However,with the development of science and technology and the diversification of electronic products,it's urgent need to develop LIB technology of high performance to meet the increasing social demand.Electrodes as the core components of LIB is a key link in the development process of the excellent performance LIB technology.Therefore,the exploration of new LIB electrode materials and modification studies of electrode materials are attracting the attention of many researchers,and become hot researches in this field.Since Tarascon et al[1]first reported and analyzed transition metal oxide?TMOs,M = Co,Ni,Cu etc.?has good electrochemical performance,TMOs as potential anode materials have obtain high attention.Among these alternative TMOs,copper oxides get attention due to its high theoretical specific capacity,nontoxic,cheap and environment friendly etc.This paper carries out the work around the preparation,modification of copper oxides with different composition,phase structure,morphology and electrochemical performances and so on;Combined with XRD,SEM,TEM characterizations et al,this paper mainly discusses the influence of preparation conditions?calcination temperature,hydrothermal treatment,etc.?,organic modification on the morphology,composition,crystal phase structure and electrochemical performances of copper-based anode materials.In this paper,the main research contents and results are as follows:1.Cube Cu₂O precursor?Cu₂O-raw?was synthesised by chemical precip-itation method,and the influence of calcination combined with alkali treat-ment and hydrothermal conditions on composition,structure,morphology and electrochemical performances of copper oxides were studied.The composition of Cu₂O-200 and Cu₂O-500 samples transform from single component Cu₂O-raw into Cu₂O-CuO mixed phase and CuO,respectively.Cu₂O-raw,Cu₂O-200 and Cu₂O-500 samples were treated by 2M NaOH solution,respecttively.Results show that,compared with untreated,Cu₂O-200-OH and Cu₂O-OH samples showed similar flower morphology,specific surface area is bigger,the capacity have the obvious improvement than untreated,the capacity increased from 70 mAh·g-1 and 85 mAh·g-1 to 105 mAh·g-1 and 200 mAh·g-1,respectively?0.5 C?;And Cu₂O-500-OH remain cube morphology,discharge specific capacity have no significant changes than untreated.Obviously,copper-based anode materials of different morphology and discharge specific capacity can be obtained by the control of calcination temperature and alkali treatment technology.Its CuO-Cu₂O mixture phase,after the hydrothermal treatment of Cu₂O and its special capacity?100 mAh·g-1,0.5 C?is higher than the Cu₂O-raw and CuO-500 samples?70 mAh·g-1,0.5 C?,and the influence of morphology on the electrochemical performances were analyzed.The morphology of copper oxide have an effect on their electrochemical properties,the results show that the "flower" and the "brick block"morphology?Cu₂O-200-OH,Cu₂O-OH and Cu₂O-H2O?of the copper oxide relative to "cube" morphology?Cu₂O-raw,Cu₂O-200 and Cu₂O-500?,have biger specific surface area,have more insertion lithium sites,can shorten the lithium ion diffusion path,and have relative high discharge specific capacity,which illustrate the morphology has direct influence on the electrochemical performances of anode materials.Although the special capacity of the CuO-raw prepared by the calcination of Cu₂O-raw by 500?is not high,but its cycle performance is relatively stable.So this paper consider the organic modification of CuO-raw by oxidation graphene?GO?and dopamine?DA?,and research the electroche-mical properties by XRD,UV,SEM,TEM characterrizations et al.2.CuO/PDA nanopcomosites were successfully prepared by dopamine?DA?and their electrochemical performances were studied.TEM,IR and UV characterizations results can determine the CuO/PDA nanocomposites was synthesized successfully.Compared with CuO-raw,CuO/PDA has dramati-cally improved the initial specific capacity,nearly 10 times that of the CuO-raw.After 100 times cycles,the discharge specific capacity increased from 67 mAh·g-1 to 92 mAh·g-1,the results show that the PDA as the the surface modification agent of CuO-raw is effective.3.CuO/GO nanopcomosites were successfully prepared by oxidation gra-phene?GO?and their electrochemical performances were studied.Compared with the original CuO-raw,CuO/GO nanocomposites initial special capacity showed increasing trend.The initial specific capacity of CuO/GO-20 samples is 11.5 times that of CuO-raw samples and discharge specific capacity is 3.6 times.Compared with CuO/GO-20,in spite of CuO/GO-40 in which GO quantity increases,the initial capacity is slightly lower,reached 11.3 times that of CuO-raw samples,discharge special capacity was 5;0 times of CuO-raw samples,but the circulation stability of CuO/GO-40 is poor than CuO/GO-20 and CuO/GO-10 samples.