微反应器-共沉淀法制备LiCoPO_4/C及其电化学性能
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摘要
采用微反应器-共沉淀法制备锂离子电池正极材料LiCoPO_4,并对LiCoPO_4进行碳包覆改性研究,分别用X线衍射(XRD)、电感耦合等离子体(ICP)、场发射电子显微镜(FESEM)、透射电子显微镜(TEM)和电化学测试系统对样品进行表征。结果表明:制得的LiCoPO_4颗粒尺寸在200 nm左右,在650℃煅烧温度下,首次放电比容量最佳。经过碳包覆改性之后,颗粒表面包覆了一层碳层,首次放电比容量和循环性能均得到明显提升,在650℃煅烧温度下制备的LiCoPO_4/C复合材料,首次放电比容量达到130 m A·h/g,经过20次循环后还剩70 m A·h/g左右。
LiCoPO_4,as cathode material,was prepared by micro-reactor and co-precipitation method,and its property was further explored by carbon coating. The prepared samples were characterized by X ray diffraction( XRD),inductively coupled plasma( ICP),field emission scanning electron microscopy( FESEM),transmission electron microscopy( TEM) and electrochemical tests.Results showed that the average particle size of prepared LiCoPO_4 was about 200 nm and the best first discharge capacity was obtained for the sample calcined at 650 ℃. After carbon coating,a uniform layer of carbon was observed on the particles,and the first discharge capacity and cycle performance surface of were promoted obviously.The first discharge capacity of LiCoPO_4/C composite calcined at 650 ℃ reached 130 m A·h/g and the capacity remained at 70 m A·h/g after 20 cycles.
LiCoPO_4,as cathode material,was prepared by micro-reactor and co-precipitation method,and its property was further explored by carbon coating. The prepared samples were characterized by X ray diffraction( XRD),inductively coupled plasma( ICP),field emission scanning electron microscopy( FESEM),transmission electron microscopy( TEM) and electrochemical tests.Results showed that the average particle size of prepared LiCoPO_4 was about 200 nm and the best first discharge capacity was obtained for the sample calcined at 650 ℃. After carbon coating,a uniform layer of carbon was observed on the particles,and the first discharge capacity and cycle performance surface of were promoted obviously.The first discharge capacity of LiCoPO_4/C composite calcined at 650 ℃ reached 130 m A·h/g and the capacity remained at 70 m A·h/g after 20 cycles.
引文
[1]AMINE K,YASUDA H,YAMACHI M.Olivine Li Co PO4as 4.8 V electrode material for lithium batteries[J].Electrochemical and solid-state letters,2000,3(4):178.
[2]PADHI A K,NANJUNDASWAMY K,GOODENOUGH J B.Phospho-olivines as positive-electrode materials for rechargeable lithium batteries[J].Journal of electrochemical society,1997,144(4):1188.
[3]RABANAL M E,GUTIERREZ M C,GARCIA-ALVARADO F,et al.Improved electrode characteristics of olivine:Li Co PO4processed by high energy milling[J].Journal of power sources,2006,160(1):523.
[4]WOLFENSTINE J,LEE U,POESE B,et al.Effect of oxygen partial pressure on the discharge capacity of Li Co PO4[J].Journal of power sources,2005,144(1):226.
[5]RAVET N,CHOUINARD Y,MAGNAN J F,et al.Electroactivity of natural and synthetic triphylite[J].Journal of power sources,2001,97(1):503.
[6]ALLEN J L,JOW T R,WOLFENSTINE J.Improved cycle life of Fe-substituted Li Co PO4[J].Journal of power sources,2011,196(20):8656.
[7]LI C,ZHANG H P,FU L J,et al.Cathode materials modified by surface coating for lithium ion batteries[J].Electrochimica acta,2006,51(19):3872.
[8]LIU J,CONRY T E,SONG X,et al.Spherical nanoporous Li Co PO4/C composites as high performance cathode materials for rechargeable lithium-ion batteries[J].Journal of materials chemistry,2011,21(27):9984.
[9]WOLFENSTINE J,ALLEN J.Li Ni PO4-Li Co PO4solid solutions as cathodes[J].Journal of power sources,2004,136(1):150.
[10]NAKAYAMA M,GOTO S,UCHIMOTO Y,et al.Changes in electronic structure between cobalt and oxide ions of lithium cobalt phosphate as 4.8 V positive electrode material[J].Chemistry of materials,2004,16(18):3399.
[11]王绍亮,唐致远,沙鸥,等.溶胶-凝胶法制备Li Co PO4及其电化学性能[J].物理化学学报,2012,28(2):343.
[12]张志鹏,严鹏,朱华君,等.微反应器-固相法制备Li MPO4(M=Fe,Mn,Co)及其性能研究[J].化工新型材料,2015,43(7):185.
[13]陈云超,余勇,王国静,等.微通道反应器-固相法制备锂离子电池正极材料Li Mn PO4/C[J].南京工业大学学报(自然科学版),2017,39(3):16.
[2]PADHI A K,NANJUNDASWAMY K,GOODENOUGH J B.Phospho-olivines as positive-electrode materials for rechargeable lithium batteries[J].Journal of electrochemical society,1997,144(4):1188.
[3]RABANAL M E,GUTIERREZ M C,GARCIA-ALVARADO F,et al.Improved electrode characteristics of olivine:Li Co PO4processed by high energy milling[J].Journal of power sources,2006,160(1):523.
[4]WOLFENSTINE J,LEE U,POESE B,et al.Effect of oxygen partial pressure on the discharge capacity of Li Co PO4[J].Journal of power sources,2005,144(1):226.
[5]RAVET N,CHOUINARD Y,MAGNAN J F,et al.Electroactivity of natural and synthetic triphylite[J].Journal of power sources,2001,97(1):503.
[6]ALLEN J L,JOW T R,WOLFENSTINE J.Improved cycle life of Fe-substituted Li Co PO4[J].Journal of power sources,2011,196(20):8656.
[7]LI C,ZHANG H P,FU L J,et al.Cathode materials modified by surface coating for lithium ion batteries[J].Electrochimica acta,2006,51(19):3872.
[8]LIU J,CONRY T E,SONG X,et al.Spherical nanoporous Li Co PO4/C composites as high performance cathode materials for rechargeable lithium-ion batteries[J].Journal of materials chemistry,2011,21(27):9984.
[9]WOLFENSTINE J,ALLEN J.Li Ni PO4-Li Co PO4solid solutions as cathodes[J].Journal of power sources,2004,136(1):150.
[10]NAKAYAMA M,GOTO S,UCHIMOTO Y,et al.Changes in electronic structure between cobalt and oxide ions of lithium cobalt phosphate as 4.8 V positive electrode material[J].Chemistry of materials,2004,16(18):3399.
[11]王绍亮,唐致远,沙鸥,等.溶胶-凝胶法制备Li Co PO4及其电化学性能[J].物理化学学报,2012,28(2):343.
[12]张志鹏,严鹏,朱华君,等.微反应器-固相法制备Li MPO4(M=Fe,Mn,Co)及其性能研究[J].化工新型材料,2015,43(7):185.
[13]陈云超,余勇,王国静,等.微通道反应器-固相法制备锂离子电池正极材料Li Mn PO4/C[J].南京工业大学学报(自然科学版),2017,39(3):16.