【摘要】：鋰離子電池其有能量密度高、循環(huán)壽命長(zhǎng)、無(wú)記憶效應(yīng)等一系列優(yōu)點(diǎn),近年來(lái)逐漸成為新能源研究應(yīng)用領(lǐng)域的主要研究方向之一。電極材料對(duì)鋰離子電池的性能有著重要影響,其中過(guò)渡金屬氧化物負(fù)極材料具有遠(yuǎn)高于碳類負(fù)極材料的理論容量而成為研究的熱點(diǎn)。尖晶石型鈷酸鹽由于具有較高的放電比容量及熱穩(wěn)定性,低毒性、低成本等優(yōu)點(diǎn)而備受人們關(guān)注。但其充放電過(guò)程中體積變化大、導(dǎo)電性差等缺點(diǎn)制約了其應(yīng)用和進(jìn)一步發(fā)展。研究表明,通過(guò)納米化、形貌調(diào)控及元素?fù)诫s等可有效改善上述問(wèn)題,從而有效提高其電化學(xué)性能。本文以ZnCo2O4作為研究對(duì)象,以硝酸鋅為鋅源、硝酸鈷為鈷源、尿素為沉淀劑及CTAB為表面活性劑,采用溶劑熱法制備前驅(qū)體,再經(jīng)高溫煅燒制得ZnCo2O4粉體。試驗(yàn)中,首先對(duì)尿素/CTAB比、加熱溫度、保溫時(shí)間、煅燒溫度等不同工藝參數(shù)用控制變量法進(jìn)行對(duì)比實(shí)驗(yàn),研究它們對(duì)材料結(jié)構(gòu)、形貌及電化學(xué)性能的影響,在此基礎(chǔ)上優(yōu)選出最佳試驗(yàn)條件,所制備電池經(jīng)50次循環(huán)后的放電比容量仍達(dá)261.9mAh/g。對(duì)結(jié)構(gòu)中Co位原子進(jìn)行了 Fe元素?fù)诫s,研究不同摻Fe量對(duì)材料結(jié)構(gòu)、形貌以及電化學(xué)性能的影響。研究表明,Fe摻雜可有效提高電池的循環(huán)穩(wěn)定性,其中ZnCo1.6Fe0.4O4經(jīng)50次循環(huán)后的放電比容量高達(dá)296.8mAh/g。鑒于鎳基氧化物具有較高的倍率性能,本文還研究了 Ni元素?fù)诫s的影響。對(duì)于ZnCo2-xNixO4,當(dāng)x=0.2時(shí),所制得材料具有較好的循環(huán)性能和倍率性能,在電流密度100mA/g下循環(huán)50次后的放電比容量仍能達(dá)到352mAh/g,顯示出良好的應(yīng)用前景。
[Abstract]:Lithium ion battery has a series of advantages such as high energy density, long cycle life, no memory effect and so on. In recent years, lithium ion battery has gradually become one of the main research directions in the field of new energy research and application. Electrode materials have an important impact on the performance of lithium ion batteries, among which transition metal oxide anode materials have much higher theoretical capacity than carbon negative electrode materials and become the focus of research. Spinel cobalt salts have attracted much attention due to their high discharge specific capacity, thermal stability, low toxicity and low cost. However, its application and further development are restricted by its large volume change and poor conductivity during charge and discharge. The results show that the above problems can be effectively improved by nanocrystalline, morphology control and element doping, and their electrochemical properties can be improved effectively. In this paper, ZnCo2O4 precursor was prepared by solvothermal method with zinc nitrate as zinc source, cobalt nitrate as cobalt source, urea as precipitant and CTAB as surfactant, and then ZnCo2O4 powder was prepared by high temperature calcination. In the experiment, the effects of urea / CTAB ratio, heating temperature, holding time and calcination temperature on the structure, morphology and electrochemical properties of the materials were studied by controlling variable method. After 50 cycles, the discharge specific capacity of the battery is still up to 261.9 mAh/ g. The Co atoms in the structure were doped with Fe elements. The effects of different Fe contents on the structure, morphology and electrochemical properties of the materials were investigated. The results show that Fe doping can effectively improve the cycle stability of the battery. The specific discharge capacity of ZnCo1.6Fe0.4O4 after 50 cycles is up to 296.8 mAh / g. In view of the high rate performance of nickel based oxides, the effect of doping of Ni elements was also studied. For ZnCo2-xNixO4, with x = 0.2, the material has good cycling performance and rate performance, and the discharge specific capacity of the material after 50 cycles at current density 100mA/g can still reach 352 mAh / g, which shows a good application prospect.
【學(xué)位授予單位】：大連海事大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM912

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本文編號(hào)：2416433