【摘要】：近年來(lái)，隨著對(duì)清潔環(huán)境和可持續(xù)能源的巨大需求，鋰離子電池受到了越來(lái)越多的關(guān)注。鋰離子電池以其高電壓、高容量、長(zhǎng)壽命、無(wú)記憶效應(yīng)和對(duì)環(huán)境友好等優(yōu)點(diǎn)成為電池發(fā)展的趨勢(shì)和研究的熱點(diǎn)。 以LiMnPO4為正極材料的電池具有較高的能量密度，因?yàn)長(zhǎng)iMnPO4理論比容量為170mAh·g-1，相對(duì)于Li+/Li的電極電勢(shì)為4.1V，能量密度約為697Wh kg-1，因此受到了越來(lái)越多的關(guān)注。此外，該材料的充放電平臺(tái)也是處在當(dāng)前通用的碳酸酯基電解質(zhì)的穩(wěn)定電化學(xué)窗口內(nèi)。同時(shí)，合成LiMnPO4的原料成本低、對(duì)環(huán)境友好，因此具有較大的應(yīng)用潛力。 本文使用高溫固相法和水熱法制備了LiMnPO4/C復(fù)合材料，考察了各種因素對(duì)LiMnPO4性能的影響，分別確定了最佳的制備工藝。 考察了碳含量、煅燒溫度、煅燒時(shí)間對(duì)LiMnPO4/C復(fù)合材料電化學(xué)性能的影響，優(yōu)化出了最佳的合成工藝，當(dāng)碳包覆量為8wt.%，煅燒溫度是650℃，煅燒時(shí)間為8h時(shí)，所合成的LiMnPO4/C正極復(fù)合材料具有最好的電化學(xué)性能，在0.1C下的放電比容量為105mAh·g-1。在此基礎(chǔ)上，改善了高溫固相法，在球磨時(shí)加入表面活性劑PVP，球磨后得到了粒徑更小，更均勻的前驅(qū)體。這有助于得到碳包覆均勻，粒徑分布均勻的LiMnPO4/C，最終所制得的LiMnPO4/C在0.1C下的放電比容量為134mAh·g-1。 優(yōu)化了水熱制備LiMnPO4/C正極復(fù)合材料的工藝，考察了碳包覆，水熱溫度，水熱時(shí)間和CTAB加入量對(duì)LiMnPO4/C電化學(xué)性能的影響。最終確定最佳的合成條件是：碳含量為8wt.%，，水熱溫度是190℃，水熱時(shí)間是24小時(shí)，CTAB的用量為L(zhǎng)iMnPO4摩爾數(shù)的一半。此條件下合成的LiMnPO4/C正極復(fù)合材料具有優(yōu)異的電化學(xué)性能，0.05C下的放電比容量為170mAh·g-1，1C下放電比比容量是131mAh·g-1，5C下放電比容量是100mAh·g-1，而且具有良好的循環(huán)性能。
[Abstract]:In recent years, with the great demand for clean environment and sustainable energy, lithium ion batteries have attracted more and more attention. Lithium ion batteries have become the trend and research focus of battery development due to their advantages of high voltage, high capacity, long life, no memory effect and environmental friendliness. The battery with LiMnPO4 as cathode material has high energy density, because the theoretical specific capacity of LiMnPO4 is 170mAh g-1 and the potential of electrode is 4.1 V relative to that of Li / Li. Therefore, the energy density of Li / Li is about 697Wh kg-1,. Therefore, more and more attention has been paid to the energy density of the battery. In addition, the charging and discharging platform of this material is also in the stable electrochemical window of the current common carbonate electrolyte. At the same time, the raw material cost of synthesizing LiMnPO4 is low, and it is environmentally friendly, so it has great application potential. In this paper, LiMnPO4/C composites were prepared by high temperature solid state method and hydrothermal method. The effects of various factors on the properties of LiMnPO4 were investigated and the optimum preparation process was determined. The effects of carbon content, calcination temperature and calcination time on the electrochemical properties of LiMnPO4/C composites were investigated. The optimum synthesis process was optimized. When the amount of carbon coating was 8 wt., the calcination temperature was 650 鈩

本文編號(hào)：2317206