Study of Lithium Silicide Nanoparticles as Anode Materials for Advanced Lithium Ion Batteries,ACS Applied Materials & Interfaces

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Study of Lithium Silicide Nanoparticles as Anode Materials for Advanced Lithium Ion Batteries
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2017-04-28 00:00:00 , DOI: 10.1021/acsami.6b16773
Xuemin Li ₁ , Faith E. Kersey-Bronec ₁ , John Ke ₁ , Jacqueline E. Cloud ₁ , Yonglong Wang ₁ , Chilan Ngo ₁ , Svitlana Pylypenko ₁ , Yongan Yang ₁

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The development of high-performance silicon anodes for the next generation of lithium ion batteries (LIBs) evokes increasing interest in studying its lithiated counterpart—lithium silicide (Li_xSi). In this paper we report a systematic study of three thermodynamically stable phases of Li_xSi (x = 4.4, 3.75, and 2.33) plus nitride-protected Li_4.4Si, which are synthesized via the high-energy ball-milling technique. All three Li_xSi phases show improved performance over that of unmodified Si, where Li_4.4Si demonstrates optimum performance with a discharging capacity of 3306 (mA h)/g initially and maintains above 2100 (mA h)/g for over 30 cycles and above 1200 (mA h)/g for over 60 cycles at the current density of 358 mA/g of Si. A fundamental question studied is whether different electrochemical paradigms, that is, delithiation first or lithiation first, influence the electrode performance. No significant difference in electrode performance is observed. When a nitride layer (Li_xN_ySi_z) is created on the surface of Li_4.4Si, the cyclability is improved to retain the capacity above 1200 (mA h)/g for more than 80 cycles. By increasing the nitridation extent, the capacity retention is improved significantly from the average decrease of 1.06% per cycle to 0.15% per cycle, while the initial discharge capacity decreases due to the inactivity of Si in the Li_xN_ySi_z layer. Moreover, the Coulombic efficiencies of all Li_xSi-based electrodes in the first cycle are significantly higher than that of a Si electrode (∼90% vs 40–70%).

中文翻译：

硅化锂纳米粒子作为高级锂离子电池负极材料的研究

用于下一代锂离子电池（LIB）的高性能硅阳极的开发引起了人们对其研究锂化硅化锂（Li _x Si）的兴趣。在本文中，我们报告了通过高能球磨技术合成的Li _x Si的三个热力学稳定相（x = 4.4、3.75和2.33）以及氮化物保护的Li _4.4 Si的系统研究。Li _x Si的所有三个相均表现出比未改性的Si更高的性能，其中Li _4.4Si表现出最佳性能，最初的放电容量为3306（mA h）/ g，并在358的电流密度下保持超过2100（mA h）/ g超过30个循环，并保持超过1200（mA h）/ g超过60个循环。 mA / g的Si。研究的一个基本问题是，不同的电化学范例（即先进行脱锂还是先进行锂化）是否会影响电极性能。没有观察到电极性能的显着差异。在Li _4.4的表面上形成氮化物层（Li _x N _y Si _z）时Si，提高了可循环性，以在超过80个循环中保持高于1200（mA h）/ g的容量。通过增加氮化程度，容量保持率从每周期的平均下降1.06％到每周期的0.15％显着提高，而初始放电容量由于Li _x N _y Si _z层中Si的惰性而下降。此外，在第一个循环中，所有基于Li _x Si的电极的库仑效率均显着高于Si电极（约90％对40-70％）。

更新日期：2017-05-04

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