Ab Initio Simulations of Li/Pyrite- MS2 ( M = Fe , Ni ) Battery Cells
Ab Initio Simulations of Li/Pyrite- MS2 ( M = Fe , Ni ) Battery Cells
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DOI：
10.1149/1.3365019
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发表时间：
2010-06
影响因子：
3.9
通讯作者：
Y. Yamaguchi;T. Takeuchi;H. Sakaebe;H. Kageyama;Hiroshi Senoh;T. Sakai;K. Tatsumi
中科院分区：
文献类型：
--
作者：
Y. Yamaguchi;T. Takeuchi;H. Sakaebe;H. Kageyama;Hiroshi Senoh;T. Sakai;K. Tatsumi
使用密度泛函理论模拟了Li/黄铁矿-MS 2 (M = Fe, Ni)二次电池的充放电循环模型的电化学能量分布。对于MS 2 在足够的Li离子浓度下的完全放电反应，计算结果表明，最终产物是Li 2 S和M金属，通过通常建议的Li 2 MS 2 （M = Ni未知）的中间化合物，该中间产物继续自分解为Li 2 MS 2 → MS + Li 2 S。对于阴极的完全充电反应Li 2 S + M金属，初始黄铁矿FeS 2 的再现是更有利的方案比其他硫化铁（FeS和Fe 3 S 4 ）的产生量多，表明Li/FeS 2 电池具有可逆充放电循环的能力。然而，对于Li/NiS 2 ，由于NiS 2 和其他镍硫化物(NiS、Ni 3 S 2 和Ni 3 S 4 )之间更接近的形成焓，因此难以再现初始黄铁矿NiS 2 。这是Li/FeS 2 电池在实验上表现出比Li/NiS 2 更好的充放电循环性能的原因之一。开路电压（OCV）的温度依赖性也使用能斯特方程来估计，即吉布斯自由能的变化，该变化源自应用密度泛函微扰理论对晶格进行声子计算获得的焓和熵。 0-100℃温度范围内OCV的温度依赖性很小，热力学标准状态下的最大OCV（Li/FeS 2 为1.67 V，Li/NiS 2 为1.84 V）与实验结果一致。
An electrochemical energy profile on the charge-discharge cycle model of Li/pyrite-MS 2 (M = Fe, Ni) secondary battery cells was simulated using density functional theory. For a full-discharge reaction of MS 2 under enough Li-ion concentration, the calculated results indicate that the final products are Li 2 S and M metal via the intermediate compound of commonly suggested Li 2 MS 2 (unknown for M = Ni), which is the intermediate product that continues the self-decomposition as Li 2 MS 2 → MS + Li 2 S. For a full-charge reaction Li 2 S + M metal at the cathode, the reproduction of the initial pyrite FeS 2 is a more favorable scheme than the production of other iron sulfides (FeS and Fe 3 S 4 ), indicating the capability of the reversible charge-discharge cycle of Li/FeS 2 cell. However, for Li/NiS 2 , there is difficulty in the reproduction of the initial pyrite NiS 2 due to a closer formation enthalpy between NiS 2 and the other nickel sulfides (NiS, Ni 3 S 2 , and Ni 3 S 4 ). This is one of the reasons that the Li/FeS 2 cell shows an experimentally better charge-discharge cycle performance than Li/NiS 2 . The temperature dependence of the open-circuit voltage (OCV) was also estimated using the Nernst's equation, namely, the change in the Gibbs free energy derived from the enthalpy and entropy obtained by phonon calculations for the crystal lattices by applying the density functional perturbation theory. There is little temperature dependence of the OCV in the temperature range 0-100°C, and the maximum OCVs at the thermodynamic standard state (1.67 V for Li/FeS 2 and 1.84 V for Li/NiS 2 ) are consistent with the experimental results.