钠离子电池正极材料铁锰酸钠的掺杂及负极材料磷酸钛钠石墨烯包覆的制备与性能研究
发布时间：2018-08-02 16:21
【摘要】：锂离子电池作为一种可充电二次电池具有高能量密度、长寿命和安全等优点,已成为便携式电子产品中主要电源设备。近几年来,钠离子电池由于其原料丰富、价格低廉等优势成为全球能源研究领域的热点,并且在大型储能设备如智能电网和电动汽车中有良好的应用前景。电极材料作为钠离子电池发展的关键技术已经过大量研究。其中,正极材料主要分为层状过渡金属氧化物、聚阴离子型化合物等类型,负极材料主要有碳材料、合金材料和钛酸盐等类型。作为正极材料,具有商业化潜力的层状过渡金属氧化物P2-Na_(0.67)[Fe_(0.5)Mn_(0.5)]O_2不仅成本低而且理论容量值很高,但在电化学循环过程中容量衰减速度过快,循环稳定性差;聚阴离子型化合物NaTi_2(PO_4)_3由于其三维的空间结构具有良好的离子传输通道和化学稳定性,是一种理想的负极材料,但其过低的电子电导率导致钠离子在电化学过程中传输受阻,严重影响电化学性能。为了提高P2-Na_(0.67)[Fe_(0.5)Mn_(0.5)]O_2的循环稳定性和NaTi_2(PO_4)_3的电子电导率,本论文开展了以下的研究工作:(1)利用非电化学活性金属元素Zn作为掺杂剂,采用固相反应法在P2-Na_(0.67)[Fe_(0.5)Mn_(0.5)]O_2基础上掺杂少量的Zn,成功制备出P2-Na_(0.67)[Fe_(0.4)Mn_(0.55)Zn_(0.05)]O_2化合物;再在P2-Na_(0.67)[Fe_(0.2)Mn_(0.65)Ni_(0.15)]O_2基础上用少量的Zn分别替换Fe或Mn金属元素,采用固相反应法合成出系列化合物:P2-Na_(0.67)[Fe_(0.2)Mn_(0.65)Ni_(0.1)Zn_(0.05)]O_2、P2-Na_(0.67)[Fe_(0.1)Mn_(0.7)Ni_(0.15)Zn_(0.05)]O_2和P2-Na_(0.67)[Fe_(0.1)Mn_(0.7)Ni_(0.1)Zn_(0.1)]O_2。通过XRD、SEM的方法对合成产物进行材料表征,并分别将材料组装成半电池后进行电化学性能测试。掺杂后的P2-Na_(0.67)[Fe_(0.5)Mn_(0.5)]O_2循环稳定性改变不大,但P2-Na_(0.67)[Fe_(0.2)Mn_(0.65)Ni_(0.15)]O_2经过掺杂后循环稳定性得到一定的提高。(2)采用化学自组装法,利用交联剂PEI进行NaTi_2(PO_4)_3前驱体氨基化,并与氧化石墨烯(GO)在低温下进行肽键反应,最后热处理得到NaTi_2(PO_4)_3-rGO的复合材料。通过XRD、SEM的方法对合成产物进行材料表征,并组装成半在电池进行电化学性能测试。未包覆石墨烯的NaTi_2(PO_4)_3起始容量小且迅速衰减,包覆石墨烯后NaTi_2(PO_4)_3在1C倍率下有良好的循环稳定性能。
[Abstract]:As a rechargeable secondary battery with high energy density, long life and safety, Li-ion battery has become the main power supply equipment in portable electronic products. In recent years, sodium ion batteries have become a hot spot in the field of global energy research because of their abundant raw materials and low price, and have a good application prospect in large energy storage equipment such as smart grid and electric vehicles. Electrode materials as a key technology for the development of sodium ion batteries have been extensively studied. Among them, the cathode materials are mainly classified into layered transition metal oxides, polyanionic compounds and other types, while the negative electrode materials are mainly carbon materials, alloy materials and titanate. As cathode materials, the layered transition metal oxide P2-Na0.67 [Fe0.5 Mn0.5] O2 with commercial potential is not only low cost but also has high theoretical capacity, but the capacity decay rate is too fast and the cycle stability is poor during electrochemical cycling. Polyanionic compound NaTi_2 (PO_4) 3 is an ideal negative electrode material because of its good spatial structure of ion transport channel and chemical stability, but its low electronic conductivity leads to the blocking of sodium ion transport in the electrochemical process. The electrochemical performance is seriously affected. In order to improve the cyclic stability of P2-Na _ (0.67) [Fe _ (0.5) mn _ (0.5)] O _ 2 and the electronic conductivity of NaTi_2 (PO_4) _ 3, the following researches have been carried out: (1) the non-electrochemical active metal element Zn is used as dopant. 閲囩敤鍥虹浉鍙嶅簲娉曞湪P2-Na_(0.67)[Fe_(0.5)Mn_(0.5)]O_2鍩虹涓婃幒鏉傚皯閲忕殑Zn,鎴愬姛鍒跺鍑篜2-Na_(0.67)[Fe_(0.4)Mn_(0.55)Zn_(0.05)]O_2鍖栧悎鐗，
本文编号：2160000
[Abstract]:As a rechargeable secondary battery with high energy density, long life and safety, Li-ion battery has become the main power supply equipment in portable electronic products. In recent years, sodium ion batteries have become a hot spot in the field of global energy research because of their abundant raw materials and low price, and have a good application prospect in large energy storage equipment such as smart grid and electric vehicles. Electrode materials as a key technology for the development of sodium ion batteries have been extensively studied. Among them, the cathode materials are mainly classified into layered transition metal oxides, polyanionic compounds and other types, while the negative electrode materials are mainly carbon materials, alloy materials and titanate. As cathode materials, the layered transition metal oxide P2-Na0.67 [Fe0.5 Mn0.5] O2 with commercial potential is not only low cost but also has high theoretical capacity, but the capacity decay rate is too fast and the cycle stability is poor during electrochemical cycling. Polyanionic compound NaTi_2 (PO_4) 3 is an ideal negative electrode material because of its good spatial structure of ion transport channel and chemical stability, but its low electronic conductivity leads to the blocking of sodium ion transport in the electrochemical process. The electrochemical performance is seriously affected. In order to improve the cyclic stability of P2-Na _ (0.67) [Fe _ (0.5) mn _ (0.5)] O _ 2 and the electronic conductivity of NaTi_2 (PO_4) _ 3, the following researches have been carried out: (1) the non-electrochemical active metal element Zn is used as dopant. 閲囩敤鍥虹浉鍙嶅簲娉曞湪P2-Na_(0.67)[Fe_(0.5)Mn_(0.5)]O_2鍩虹涓婃幒鏉傚皯閲忕殑Zn,鎴愬姛鍒跺鍑篜2-Na_(0.67)[Fe_(0.4)Mn_(0.55)Zn_(0.05)]O_2鍖栧悎鐗，
本文编号：2160000
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