铝掺杂锰酸锂正极材料制备及第一性原理研究

Preparation and first-principles studies of doped Al in LiMnO

采用固相法制备出高纯度纳米LiAl_(0.25)Mn_(1.75)O_(4)并用此制备成半电池,对其进行充放电循环测试和阻抗测试,并与原始LiMn2O4的测试结果相比较.另采用基于密度泛函理论的第一原理方法,研究了掺铝锰酸锂LiAl_(0.25)Mn_(1.75)O_(4)的能带结构、态密度和原子布居,实验与计算分析结果表明LiAl_(0.25)Mn_(1.75)O_(4)在室温下0.01C放电时首次放电容量为124.8 mAh/h,室温0.2C下50个循环周期后放电比容量保持率可达到83.6%;LiAl_(0.25)Mn_(1.75)O_(4)的能带带隙为0.21 eV,分态密度中Al-s轨道与O-s轨道在-20 eV左右的明显杂化均表明LiAl_(0.25)Mn_(1.75)O_(4)材料具有高导电率、高结构稳定性、高比容量保持率,这为推动锂离子电池锰酸锂正极材料的发展提供理论依据.

High purity nanometer LiAl_(0.25)Mn_(1.75)O_(4) was prepared by solid phase method and used to fabricate half-cell.The charge-discharge cycle test and impedance test were performed on the half-cell,and the results were compared with the original LiMn2 O4 test results.In addition,the energy band structure,density of states and atomic population of aluminum-doped lithium manganese oxide LiAl_(0.25) Mn_(1.75)O_(4) are studied by using the first principle method based on density functional theory.The experimental and calculated results show that the first discharge capacity of LiAl_(0.25) Mn_(1.75)O_(4) is 124.8 mAh/h at 0.01 C at room temperature,and the discharge specific capacity retention can reach 83.6% after 50 cycles at 0.2 C at room temperature.The band gap of LiAl_(0.25)Mn_(1.75)O_(4) is 0.21 eV,and Al-s orbit and O-sorbit at about-20 eV in the partial density of states are obviously hybrid,indicating that LiAl_(0.25) Mn_(1.75)O_(4) material has high conductivity,high structural stability and high specific capacity retention rate.Thus,it provides theoretical basis for promoting the development of LiMn2 O4 cathode materials for Li-ion batteries.