錳基氧化物及硫化物的制備及其電化學(xué)性能研究
發(fā)布時(shí)間:2018-03-10 10:41
本文選題:MnO@Ni 切入點(diǎn):NiS_2-MnS 出處:《合肥工業(yè)大學(xué)》2017年碩士論文 論文類型:學(xué)位論文
【摘要】:錳基氧化物及硫化物納米材料因其組成和性質(zhì)的多樣性,在鋰離子電池負(fù)極材料和超級(jí)電容器電極材料方面具有廣泛的應(yīng)用。本文先通過(guò)一步共沉淀法合成微米球形碳酸鹽前軀體,再采用一步煅燒控制還原法和溶劑熱法,分別制備了MnO@Ni微米球、NiS2-MnS多級(jí)結(jié)構(gòu),并研究了它們的電化學(xué)性能。主要研究?jī)?nèi)容如下:1、以乙酸鎳和乙酸錳為原料,碳酸氫鈉為沉淀劑,先通過(guò)共沉淀法合成鎳錳碳酸鹽前驅(qū)體,再采用煅燒控制還原法,制備了 MnO@Ni微米球。采用X-射線衍射(XRD)、掃描電鏡(SEM)、射線光電子能譜(XPS)等測(cè)試手段對(duì)產(chǎn)物的物相、形貌結(jié)構(gòu)進(jìn)行了表征,研究了其作為鋰離子電池負(fù)極材料的相關(guān)電化學(xué)性能。實(shí)驗(yàn)結(jié)果表明:在所制備的幾組樣品中,當(dāng)Ni:Mn摩爾比為1:10時(shí),所得產(chǎn)物具有最好的電化學(xué)性能。在0.1 C倍率下的放電容量為851.2 mAh g-1。在0.5 C倍率下經(jīng)過(guò)200次循環(huán)后仍保持285.7 mAh g-1的放電比容量,其容量保持率為72%,具有優(yōu)異的循環(huán)穩(wěn)定性。2、以乙酸鎳和乙酸錳為原料,碳酸氫鈉為沉淀劑,通過(guò)共沉淀法合成鎳錳碳酸鹽前驅(qū)體,然后采用硫代乙酰胺在溶劑熱條件下進(jìn)行硫化,制備了 NiS2-MnS多級(jí)結(jié)構(gòu)。對(duì)產(chǎn)物的物相、形貌結(jié)構(gòu)進(jìn)行了表征,并研究了其作為超級(jí)電容器電極材料的相關(guān)電化學(xué)性能。結(jié)果表明:當(dāng)反應(yīng)溫度為150℃,反應(yīng)時(shí)間為12 h時(shí),得到硫化完全的產(chǎn)物,并具有較完整的球形結(jié)構(gòu)。在1Ag-1電流密度下其比容量為630.8 Fg-1,具有優(yōu)異的倍率性能,經(jīng)過(guò)1000次循環(huán)后,比容量為205 Fg-1,容量保持率大約為70%,具有良好的倍率性能與循環(huán)穩(wěn)定性。
[Abstract]:Manganese based oxides and sulphide nanomaterials due to their diversity in composition and properties, It has been widely used in cathode materials of lithium ion batteries and electrode materials of supercapacitors. In this paper, microsphere carbonate precursors were synthesized by one step coprecipitation method, and then one-step calcination-controlled reduction method and solvothermal method were used. The multistage structures of MnO@Ni microspheres NiS2-MnS were prepared and their electrochemical properties were studied. The main contents of the study were as follows: (1) Nickel acetate and manganese acetate were used as raw materials and sodium bicarbonate was used as precipitant to synthesize nickel-manganese carbonate precursor by co-precipitation method. The MnO@Ni microspheres were prepared by calcination-controlled reduction method. The phase and morphology of the products were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of the materials used as anode materials for lithium ion batteries were studied. The experimental results show that the Ni:Mn molar ratio is 1:10 in several groups of samples. The discharge capacity of the product is 851.2 mAh g -1 at 0. 1 C rate. The discharge capacity of 285.7 mAh g-1 is maintained at 0. 5 C rate after 200 cycles. Its capacity retention ratio is 72, and it has excellent cycling stability. Nickel manganese carbonate precursor was synthesized by co-precipitation method with nickel acetate and manganese acetate as raw materials and sodium bicarbonate as precipitant. The multistage structure of NiS2-MnS was prepared by sulfidation of thioacetamide under solvothermal conditions. The phase and morphology of the product were characterized. The electrochemical properties of the supercapacitor electrode material were studied. The results showed that when the reaction temperature was 150 鈩,
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