He Yu, Lu Xia, Kim Duck Young
Center for High Pressure Science and Technology Advanced Research Shanghai 201203 China
Key Laboratory of High-Temperature and High-Pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences Guiyang Guizhou 550081 China.
RSC Adv. 2018 Jun 4;8(36):20228-20233. doi: 10.1039/c8ra01829d. eCollection 2018 May 30.
Due to its intriguing geometry, possessing an open-channel structure, Si demonstrates potential for storing and/or transporting Li/Na ions in rechargeable batteries. In this work, first-principles calculations were employed to investigate the phase stability and Li/Na storage and transport properties of the Si anode to evaluate its electrochemical performance for batteries. The intercalation of Li and Na into the Si structure could deliver a capacity of 159 mA h g (LiSi and NaSi), and the average intercalation potentials were 0.17 V ( Li) and 0.34 V ( Na). Moreover, the volume change of Si upon intercalation proved very small (0.09% for Li, 2.81% for Na), indicating its "zero-strain" properties with stable cycling performance. Li and Na can diffuse along the channels inside the Si structure with barrier energies of 0.14 and 0.80 eV respectively, and the ionic conductivity of LiSi was calculated to be as high as 1.03 × 10 S cm at 300 K. Our calculations indicate that the fast Li-ionic conductivity properties make the Si structure a novel anode material for both lithium and sodium ion batteries.
由于其具有引人入胜的几何结构，拥有开放通道结构，硅在可充电电池中展现出存储和/或传输锂/钠离子的潜力。在这项工作中，采用第一性原理计算来研究硅阳极的相稳定性以及锂/钠存储和传输特性，以评估其在电池中的电化学性能。锂和钠嵌入硅结构可提供159 mA h g的容量（LiSi和NaSi），平均嵌入电位分别为0.17 V（锂）和0.34 V（钠）。此外，嵌入过程中硅的体积变化被证明非常小（锂为0.09%，钠为2.81%），表明其具有“零应变”特性以及稳定的循环性能。锂和钠可以分别以0.14和0.80 eV的势垒能沿着硅结构内部的通道扩散，并且计算得出LiSi在300 K时的离子电导率高达1.03×10 S cm。我们的计算表明，快速的锂离子传导特性使硅结构成为锂和钠离子电池的新型阳极材料。
