摘要
采用低温燃烧法制备出不同稀土元素掺杂的高电压镍锰酸锂(LiNi_(0.5)Mn1.5O_(4))正极材料,探究了不同掺杂比例(物质的量分数0.5%、1%、2%)和不同掺杂稀土元素(La、Ce、Yb)对样品性能的影响,并通过X射线衍射、拉曼光谱、电子顺磁共振和恒电流间歇滴定等技术探究了其影响机理。从X射线衍射图可以看出,稀土掺杂可以抑制LixNi1-xO杂质相的产生;电感耦合等离子谱结果表明,掺杂进入的稀土元素与设计比例基本相符;从拉曼光谱图可以看出,稀土元素可以使样品的有序相增多,其中Ce掺杂样品的有序相最多;结合电子顺磁共振波谱氧空位测试,发现Ce掺杂诱导了样品中有序相比例增加,从而使样品的稳定性提高;经恒电流间歇滴定技术测试发现,Ce掺杂镍锰酸锂样品的扩散系数比未掺杂样品高了约15倍;在不同掺杂比例上,1%掺杂量时样品性能最佳。在3种最佳掺杂量的稀土元素样品中,Ce掺杂的样品性能最优,首次放电比容量可以达到133.3mAh·g^(-1),比未掺杂样品放电比容量高且首次效率提高了 18%,在1C下循环200次后,容量保持率为102%,比未掺杂样品提高了 8%。
High-voltage LiNi_(0.5)Mn1.5O_(4) cathode materials doped with different rare earth elements were prepared by low temperature combustion method.The effects of different doping ratios(molar ratios of 0.5%,1%,2%) and different kinds of rare earth elements(La,Ce,Yb) on the material performance were investigated,and the influence mechanism was explored by X-ray diffraction,Raman spectrum,electron paramagnetic resonance and galvanostatic intermittent titration technique.X-ray diffraction pattern illustrates that rare earth doping can inhibit the generation of LixNi1-xO phase.The inductively coupled plasma spectroscopy illustrates that the doped rare earth elements are basically in accordance with the design proportion.Raman spectrum illustrates that rare earth elements can increase the ordered phase of the material and Ce doped sample has the most ordered phase.In combination with electron paramagnetic resonance oxygen vacancy test,it is found that Ce doped sample induces the increase of the proportion of ordered phase in the material,thus improving the stability of the material.Galvanostatic intermittent titration technique test showed that the diffusion coefficient of Ce-doped LiNi_(0.5)Mn1.5O_(4) material was about 15 times higher than the undoped sample.In different doping proportion,the material with 1% doping amount had the best performance.Among the samples doping with the best amount of three rare earth elements,Ce doped samples had the best doping performance,and the specific discharge capacity of the first discharge can reach 133.3 mAh·g^(-1),which was higher than the undoped group and the first discharge efficiency was increased by 18%.After 200 cycles at 1 C,the capacity retention rate was 102%,which was 8% higher than the undoped group.
作者
刘海志
孔志浩
林晓燕
刘鹏东
董法海
王桢
温广武
LIU Hai‑Zhi;KONG Zhi‑Hao;LIN Xiao‑Yan;LIU Peng‑Dong;DONG Fa‑Hai;WANG Zhen;WEN Guang‑Wu(School of Materials Science and Engineering,Shandong University of Technology,Zibo,Shandong 255000,China;Shandong Si-Nano Materials Technology Co.Ltd.,Zibo,Shandong 255000,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2021年第10期1782-1792,共11页
Chinese Journal of Inorganic Chemistry
关键词
镍锰酸锂
低温燃烧法
有序/无序调控
氧空位
LiNi_(0.5)Mn1.5O_(4)
low temperature combustion method
ordered/disordered regulation
oxygen vacancy
