HP-CoFe_(2)O_(4)/C锂离子电池负极材料的制备及电化学性能研究

Synthesis and electrochemical performance of HP-CoFe_(2)O_(4)/C anode material for lithiumion battery

具有高理论比容量的二元金属氧化物作为高性能锂离子电池的负极材料,正受到越来越多的关注。然而,循环期间的大体积变化极大地阻碍了负极材料在锂离子电池中的实际应用。为此,采用简单的一步水热法合成了含有吡啶-3,5-二羧酸(H2pdc)和1,10-菲罗啉(Phen)配体的新型Co、Fe双金属有机框架CoFe-MOF,以不同方法添加活性炭生成CoFe-MOF/C(1-4),然后在惰性气氛中煅烧,获得Co、Fe双金属氧化物复合材料标HP-CoFe_(2)O_(4)/C(1-4)。活性炭的结合使电池的性能更加优异,不仅可以提高电子电导率,还可以缓冲复合材料在锂化/脱锂过程中的体积变化。电化学测试表明,HP-CoFe_(2)O_(4)/C-1复合材料相对于其他掺碳方法有着更好的电化学稳定性,当电流密度为200mA/g时,该复合材料的首次放电比容量可达到984.5mA·h/g, 100次循环后仍能保持451.9mA·h/g的可逆容量。

Binary metal oxide with high theoretical specific capacities is attracting more attentions as anode materials for high performance lithium-ion batteries.Nevertheless, the large volume changes during cycles greatly hamper the actual application of anode materials in lithium-ion batteries.Herein, a new Co Fe metal organic framework(CoFe-MOF) with ligands of 3,5-Pyridinedicarboxylic acid(H2pdc) and 1,10-Phenanthroline(Phen) was synthesized using a simplistic one-step hydrothermal approach.Activated carbon was then added in different ways to generate CoFe-MOF/C(1-4),after that, CoFe-MOF/C(1-4) was calcined in an inert atmosphere to obtain Co Fe bimetal oxide(marked as HP-CoFe_(2)O_(4)/C(1-4)) composite material.The combination of activated carbon not only improved the electronic conductivity, but also buffered the volume change of the composite material during the lithiation/delithiation process, which made the performance of battery more excellent.Compared with other carbon doping methods, HP-CoFe_(2)O_(4)/C-1 composite material had better electrochemical stability.When the current density was 200 mA·g-1,the first discharge specific capacity of the composite material reached to 984.5 mA·h·g-1,and the reversible capacity of 451.9 mA·h·g-1was still maintained after 100 cycles.