CAJ | 학술논문

采用第一性原理的超软赝势平面波法,结合广义梯度近似(GGA)及 PW91算法,计算了锂离子电池正极材料LiFePO4和负极材料 Li 的电子结构和热力学性质。研究结果表明,经过几何优化与计算后,可得到电极材料LiFePO4最稳定的结构,对应的晶胞参数a=1.0294 nm,b=0.5986 nm,c=0.4675 nm。基于声子谱态密度,可以计算锂离子电池体系的热力学参数：熵(S)、焓(H )和吉布斯自由能(G)等。根据所得热力学数据作图,可拟合出相关函数表达式。其中,正极材料LiFePO4和负极材料 Li 的熵和焓均随温度升高而增大,而吉布斯自由能随温度升高而减小,这与热力学规律相符合。研究获得了锂离子电池电极材料的微观结构及热力学性质,可为锂离子电池的实际应用提供理论指导。
채용제일성원리적초연안세평면파법,결합엄의제도근사(GGA)급 PW91산법,계산료리리자전지정겁재료LiFePO4화부겁재료 Li 적전자결구화열역학성질。연구결과표명,경과궤하우화여계산후,가득도전겁재료LiFePO4최은정적결구,대응적정포삼수a=1.0294 nm,b=0.5986 nm,c=0.4675 nm。기우성자보태밀도,가이계산리리자전지체계적열역학삼수：적(S)、함(H )화길포사자유능(G)등。근거소득열역학수거작도,가의합출상관함수표체식。기중,정겁재료LiFePO4화부겁재료 Li 적적화함균수온도승고이증대,이길포사자유능수온도승고이감소,저여열역학규률상부합。연구획득료리리자전지전겁재료적미관결구급열역학성질,가위리리자전지적실제응용제공이론지도。
By using the ultrasoft pseudopotential plane wave method based on the first-principles,combing the generalized gradient approximation (GGA)and PW9 1 algorithms,the electronic structure and thermodynamic properties of electrode materials (LiFePO4 ,Li)in lithium-ion cells were calculated.The results show that the structure of the electrode material LiFePO4 was optimized and achieved the most stable state.The calculated re-sults indicated that the unit cell parameters of the electrode material LiFePO4:a=1.0294 nm,b=0.5986 nm, c=0.4675 nm.The thermodynamic parameters of LiFePO4 lithium-ion cells,such as entropy S,enthalpy H and Gibbs free energy G,were calculated by the phonon density of state.The images according to these data were made and the curves into the function expression were fitted.With the ambient temperature increasing en-tropy S and enthalpy H increased,but Gibbs free energy G decreased.This result complied with the thermody-namic law.So,the micro calculation provided the theoretical guidance about the practical application of lithium ion batteries.