Theoretical Understanding and Prediction of Lithiated Sodium Hexatitanates

详细信息    查看全文

• 作者：Yun Wang ; Haimin Zhang ; Xiangdong Yao ; Huijun Zhao
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：February 13, 2013
• 年：2013
• 卷：5
• 期：3
• 页码：1108-1112
• 全文大小：358K
• 年卷期：v.5,no.3(February 13, 2013)
• ISSN：1944-8252

文摘

Sodium hexatitanates (Na₂Ti₆O₁₃) with tunnelled structures have been experimentally proposed to be good candidates for anode materials of lithium ion batteries because of their low potential, small shape transformation, and good reversibility. The understanding of the properties of this lithiated titanate is significant for their development. To this end, the first-principle calculations were performed to investigate the interaction between Li ions and Na₂Ti₆O₁₃ at the atomic level. After structural optimization with various Li:Ti ratios, the Li ions are found to energetically prefer to stay at the small rhombic tunnels of Na₂Ti₆O₁₃, where the diffusion energy barrier of Li ions is also lower. Such preference is determined by the chemical environment around Li ions. Our theoretical intercalation potential and volume change on the basis of the optimized atomic structures agree with the experimental observations. The analysis of the electronic properties reveals the Burstein鈥揗oss effect in lithiated Na₂Ti₆O₁₃ due to the heavy n-type doping. Such materials possess high conductivity, which can benefit their applications in photoelectrochemical or electrochemical areas.

Keywords:

anode of lithium ion battery; lithiated titanate; intercalation mechanism; density functional theory; Burstein鈭扢oss effect; photocatalysis