通过酚醛树酯包覆和碳热反应在富锂正极材料表面原位构建碳和尖晶石双壳保护结构,对这种核壳结构的正极材料进行了结构和形貌表征,并研究了其电化学性能.研究发现,尖晶石相为材料提供了三维锂离子迁移通道,碳包覆层显著提高了正极材料...通过酚醛树酯包覆和碳热反应在富锂正极材料表面原位构建碳和尖晶石双壳保护结构,对这种核壳结构的正极材料进行了结构和形貌表征,并研究了其电化学性能.研究发现,尖晶石相为材料提供了三维锂离子迁移通道,碳包覆层显著提高了正极材料的电子电导率,两种效应的共同作用极大降低了材料的电化学阻抗,提升了材料的放电比容量,这种多壳层结构正极材料还具有优异的倍率性能,在5C倍率下放电比容量可达到135.1 m A·h/g.展开更多
A kind of cathode material of layered LixNiyMn1- yO2 characterized with the O2 type has been synthesized by a simple method. Its precursor NaxNiyMn1- yO2 has been prepared from manganese dioxide, nickel hydroxide and ...A kind of cathode material of layered LixNiyMn1- yO2 characterized with the O2 type has been synthesized by a simple method. Its precursor NaxNiyMn1- yO2 has been prepared from manganese dioxide, nickel hydroxide and sodium carbonate at high temperature in air and quickly cooled in cold water, then it has been exchanged by the melted LiNO3 at 300～ 400℃ in air. The effects of calcine temperature for the precursors and its compositions (the content of Na and Ni) on the electrochemical properties of the material LixNiyMn1- yO2 have been investingated by XRD and electrochemical tests. The results show that the sample Li0.7Ni0.3Mn0.7O2, has the best electrochemical properties which shows only one charge discharge potential stage of 2.8～ 3.0V and has a high specific capacity over 180mAh· g- 1 cycled between 2.0～ 4.20V. A significant structure transformation to the spinal type phase has not been found in the charge discharge cycling and the discharge specific capacity around 165mAh· g- 1 has remained after the 20th cyclings for the material.展开更多
文摘通过酚醛树酯包覆和碳热反应在富锂正极材料表面原位构建碳和尖晶石双壳保护结构,对这种核壳结构的正极材料进行了结构和形貌表征,并研究了其电化学性能.研究发现,尖晶石相为材料提供了三维锂离子迁移通道,碳包覆层显著提高了正极材料的电子电导率,两种效应的共同作用极大降低了材料的电化学阻抗,提升了材料的放电比容量,这种多壳层结构正极材料还具有优异的倍率性能,在5C倍率下放电比容量可达到135.1 m A·h/g.
文摘A kind of cathode material of layered LixNiyMn1- yO2 characterized with the O2 type has been synthesized by a simple method. Its precursor NaxNiyMn1- yO2 has been prepared from manganese dioxide, nickel hydroxide and sodium carbonate at high temperature in air and quickly cooled in cold water, then it has been exchanged by the melted LiNO3 at 300～ 400℃ in air. The effects of calcine temperature for the precursors and its compositions (the content of Na and Ni) on the electrochemical properties of the material LixNiyMn1- yO2 have been investingated by XRD and electrochemical tests. The results show that the sample Li0.7Ni0.3Mn0.7O2, has the best electrochemical properties which shows only one charge discharge potential stage of 2.8～ 3.0V and has a high specific capacity over 180mAh· g- 1 cycled between 2.0～ 4.20V. A significant structure transformation to the spinal type phase has not been found in the charge discharge cycling and the discharge specific capacity around 165mAh· g- 1 has remained after the 20th cyclings for the material.
