More and more experimental results

More and more experimental results and structural analysis confirm the two-step desodiation process in NaFePO4. During the first step, sodium is extracted from NaFePO4 through a single homogeneous phase process up to the intermediate phase, when Na2/3FePO4 forms at the voltage discontinuity (that is, a solid solution process for NaxFePO4, 1 > x> 2/3). In the second step, sodium extraction occurs in a two-phase process between a Na-rich NayFePO4 phase and a Na-poor FePO4 phase whose composition has been found to vary with overall Na content in the electrode (that is, a two-phase process between Na2/3FePO4 and FePO4). As a result, contrary to the symmetrical biphasic mechanism observed in micrometric LiFePO4, Na extraction occurs in two voltage plateaus separated by an intermediate phase NaxFePO4 (x  2/3), whereas three phases (FePO4, Na2/3FePO4 and NaFePO4) appear simultaneously during Na insertion. The crystal structure of Na2/3FePO4 has been recently studied in detail with synchrotron X-ray diffraction
and defined as a superstructure due to Na/vacancies and charge ordering. The intermediate phase at x ¼ 2/3 for NaxFePO4 is also much more stable, compared to the lithium equivalent. The large cell mismatch enhances the effects of the diffuse interface, which has a higher impact on the Na-ion than Li-ion intercalation chemistry, and therefore a reduced miscibility gap in the overall composition are observed here in micrometric materials. Recently, a detailed understanding of the intermediate phase, Na2/3FePO4, has been reported. With a variety of characterization methods, Boucher et al. proposed a three-fold superstructure for the Na2/3FePO4 intermediate phase, with a dense plane being formed by the 2/3 Na and 1/3 vacancy sub-lattice in the intermediate phase, related to the second/third shortest Na–Na distances. This finding introduces a new strategy to develop high-rate olivine cathodes for Na-ion batteries by producing grains with larger (101) surface areas.

結果 (中文) 1:

更多和更具实验性结果和结构分析证实在 NaFePO4 desodiation 步法。期间的第一步，钠从中提取 NaFePO4 通过一个单一的均相过程到中间阶段，当 Na2/3FePO4 形式在电压不连续性 (即 NaxFePO4，1 固溶工艺 > x > 2/3)。在第二步，钠提取发生在富钠 NayFePO4 相之间其组分随电极 (即 Na2/3FePO4 和 FePO4 之间的两相过程) 中的总 Na 含量 Na 穷人 FePO4 相两相的过程。结果，与对称双向机制在测微 LiFePO4 中观察到，Na 提取发生在两个电压高原相隔一个中间阶段 NaxFePO4 (x 2/3)，而三个阶段 (FePO4、 Na2/3FePO4 和 NaFePO4) 同时出现在 Na 插入。Na2/3FePO4 的晶体结构已被最近详细研究了与同步辐射 x 射线衍射并定义作为上层建筑 Na/空缺和电荷订购。中间阶段在 x ¼ 月 2 日/3 日的 NaxFePO4 也是稳定得多，相比锂当量。大细胞不匹配提高的影响，弥漫性的接口，对钠离子比锂离子插层化学有较高的影响，并因此在测微材料这里观察整体组成的减少相溶性差距。最近，详细了解的中间阶段，Na2/3FePO4，据报。与各种表征方法，鲍彻等人提出了三倍的上层建筑 Na2/3FePO4 的中间阶段，与正在形成的 2/3 Na 和 1/3 空缺分格在中间阶段，有关第二次、 三次最短的娜娜 — — 距离密集平面。这一发现介绍了新的战略，发展高率橄榄石阴极的钠离子电池生产颗粒具有较大的 (101) 表面面积。

結果 (中文) 3:

越来越多的实验结果与结构分析nafepo4确认两步desodiation过程。在第一步中，钠是通过一个单一的均相过程的中间阶段nafepo4提取，当钠/ 3fepo4形式在电压不连续性（即一个naxfepo4，1 > x > 2 / 3固溶处理）。第二步，钠提取发生在两相中富含钠nayfepo4相和那可怜的FePO4相的成分已被发现与总体钠含量变化之间的电极（即钠/ 3fepo4和FePO4两相之间的一个过程）。作为一个结果，相反，在微米级LiFePO4观察对称双向机制，NA提取发生在中间阶段naxfepo4分隔开的两个电压平台（×2／3），而三阶段（FePO4，钠/ 3fepo4和nafepo4）同时出现在那插入。钠/ 3fepo4晶体结构最近已详细研究了同步辐射X射线衍射由于钠/空缺和电荷有序的超结构定义。中间相的X¼2 / 3 naxfepo4也更稳定，比等量的锂。大细胞错配增强的扩散界面的影响，这对钠离子比锂离子插层化学的影响较大，因此在这里观察到微米级的材料是降低混溶隙中的整体组成。最近，一个详细的了解的中级阶段，钠/ 3fepo4，已报道。有多种表征方法，布歇等人。提出了一三倍的上层建筑为Na2 / 3fepo4中级阶段，随着密集的飞机的2／3和1／3的空位子那格子中间相的形成，第二/第三短距离相关的–NA NA。这一发现引入了一个新的战略，开发高率的橄榄石阴极钠离子电池生产的谷物与较大（101）的表面面积。