Ti‐Substituted NaNi0.5Mn0.5‐xTixO2 Cathodes with Reversible O3−P3 Phase Transition for High‐Performance Sodium‐Ion Batteries,Advanced Materials

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Ti‐Substituted NaNi0.5Mn0.5‐xTixO2 Cathodes with Reversible O3−P3 Phase Transition for High‐Performance Sodium‐Ion Batteries
Advanced Materials ( IF 27.4 ) Pub Date : 2017-03-15 , DOI: 10.1002/adma.201700210
Peng-Fei Wang _{1,

2} , Hu-Rong Yao _{1,

2} , Xin-Yu Liu ₃ , Jie-Nan Zhang ₃ , Lin Gu ₃ , Xi-Qian Yu ₃ , Ya-Xia Yin _{1,

2} , Yu-Guo Guo _{1,

2}

Affiliation

Sodium‐ion batteries (SIBs) have been considered as potential candidates for stationary energy storage because of the low cost and wide availability of Na sources. O3‐type layered oxides have been considered as one of the most promising cathodes for SIBs. However, they commonly show inevitable complicated phase transitions and sluggish kinetics, incurring rapid capacity decline and poor rate capability. Here, a series of sodium‐sufficient O3‐type NaNi_0.5Mn_0.5‐ _x Ti _x O₂ (0 ≤ x ≤ 0.5) cathodes for SIBs is reported and the mechanisms behind their excellent electrochemical performance are studied in comparison to those of their respective end‐members. The combined analysis of in situ X‐ray diffraction, ex situ X‐ray absorption spectroscopy, and scanning transmission electron microscopy for NaNi_0.5Mn_0.2Ti_0.3O₂ reveals that the O3‐type phase transforms reversibly into a P3‐type phase upon Na+ deintercalation/intercalation. The substitution of Ti for Mn enlarges interslab distance and could restrain the unfavorable and irreversible multiphase transformation in the high voltage regions that is usually observed in O3‐type NaNi_0.5Mn_0.5O₂, resulting in improved Na cell performance. This integration of macroscale and atomicscale engineering strategy might open up the modulation of the chemical and physical properties in layered oxides and grasp new insight into the optimal design of high‐performance cathode materials for SIBs.

中文翻译：

具有高性能O3-P3可逆O3-P3相变的Ti替代NaNi0.5Mn0.5-xTixO2阴极，用于高性能钠离子电池

钠离子电池（SIB）被认为是固定能量存储的潜在候选者，因为其价格低廉且钠源的可用性广泛。O3型层状氧化物被认为是SIB最有希望的阴极之一。然而，它们通常显示出不可避免的复杂相变和缓慢的动力学，导致容量快速下降和差的速率容量。这里是一系列钠含量充足的O3型NaNi _0.5 Mn _0.5- _x Ti _x O ₂（0≤x 报道了SIBs阴极≤0.5）的阴极，并研究了它们出色的电化学性能背后的机理，并与它们各自的末端成员进行了比较。NaNi _0.5 Mn _0.2 Ti _0.3 O _2的原位X射线衍射，非原位X射线吸收光谱和扫描透射电子显微镜的综合分析显示，Na +时O3型相可逆地转变为P3型相脱嵌/插层。用Ti代替Mn可以延长板间距离，并且可以抑制在高压区域发生的不利和不可逆的多相转变，这种转变通常在O3型NaNi _0.5 Mn _0.5 O _2中观察到，从而改善了Na电池的性能。宏观和原子尺度工程策略的这种整合可能会打开对层状氧化物化学和物理性质的调节，并为SIB的高性能阴极材料的最佳设计掌握新的见识。

更新日期：2017-03-15

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