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Synthesis and Redox Mechanism of Cation-Disordered, Rock-Salt Cathode-Material Li–Ni–Ti–Nb–O Compounds for a Li-Ion Battery
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2019-09-17 , DOI: 10.1021/acsami.9b12822
Zhenlu Yu 1 , Xingyu Qu 1 , Aichun Dou 1 , Mingru Su 1 , Yunjian Liu 1 , Feixiang Wu
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2019-09-17 , DOI: 10.1021/acsami.9b12822
Zhenlu Yu 1 , Xingyu Qu 1 , Aichun Dou 1 , Mingru Su 1 , Yunjian Liu 1 , Feixiang Wu
Affiliation
Cation-disordered oxide materials working as cathodes for Li-ion batteries have been at a standstill because of their structurally limited specific capacities (below 175 mAh g–1 in most cases). In this work, we have introduced 4d0 Nb5+ into host material LiNi0.5Ti0.5O2 to synthesize Ni-based cation-disordered Fm3̅m Li–Ni–Ti–Nb–O compounds of Li1+x/100Ni1/2–x/100Ti1/2–x/100Nbx/100O2 (x = 0, 5, 10, 15, 20) through a sol–gel method, showing particle sizes of less than 200 nm. Taking Li1.2Ni0.3Ti0.3Nb0.2O2 with the best performance (an average voltage of ∼2.7 V and high discharge capacity of 221.5 mAh g–1) among oxides as a model, we study the relationship between the structure, morphology, redox mechanism, and electrochemical performance of cation-disordered oxides through a combination of X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption near-edge spectroscopy tests and in situ XRD with electrochemistry. The obtained results indicate that the improved capacity is mainly ascribed to Nb5+, which optimizes the Ni2+/Ni4+ practical capacity and effectively stabilizes the O2–/O– redox reaction. The results emphasize that Li–Ni–Ti–Nb–O compounds are promising members in the family of cation-disordered transition-metal oxide materials.
中文翻译:
锂离子电池用阳离子无序岩盐阴极材料Li-Ni-Ti-Nb-O的合成及氧化还原机理
用作锂离子电池阴极的无序氧化物材料由于其结构上有限的比容量(在大多数情况下低于175 mAh g –1)而处于停顿状态。在这项工作中,我们已经引入了图4d 0的Nb 5+为主体材料的LiNi 0.5的Ti 0.5 Ò 2合成的Ni基阳离子无序FM 3米的Li的LiNi钛-铌-O化合物1+ X / 100的Ni 1 / 2– x / 100 Ti 1 / 2– x / 100 Nb x / 100 O 2(x= 0、5、10、15、20)通过溶胶-凝胶法显示出小于200 nm的粒径。以性能最好的Li 1.2 Ni 0.3 Ti 0.3 Ti 0.3 Nb 0.2 O 2(平均电压约为2.7 V,高放电容量为221.5 mAh g –1)作为氧化物模型,我们通过X射线衍射(XRD),扫描电子显微镜,透射电子显微镜,X-射线衍射研究了阳离子无序氧化物的结构,形态,氧化还原机理和电化学性能之间的关系。射线光电子能谱,X射线吸收近边缘能谱测试以及电化学原位XRD。结果表明,提高的容量主要归因于Nb 5+,从而优化了Ni 2+ / Ni 4+的实际容量并有效地稳定了O 2– / O –氧化还原反应。结果强调,Li-Ni-Ti-Nb-O化合物是阳离子无序过渡金属氧化物材料家族中有希望的成员。
更新日期:2019-09-18
中文翻译:
锂离子电池用阳离子无序岩盐阴极材料Li-Ni-Ti-Nb-O的合成及氧化还原机理
用作锂离子电池阴极的无序氧化物材料由于其结构上有限的比容量(在大多数情况下低于175 mAh g –1)而处于停顿状态。在这项工作中,我们已经引入了图4d 0的Nb 5+为主体材料的LiNi 0.5的Ti 0.5 Ò 2合成的Ni基阳离子无序FM 3米的Li的LiNi钛-铌-O化合物1+ X / 100的Ni 1 / 2– x / 100 Ti 1 / 2– x / 100 Nb x / 100 O 2(x= 0、5、10、15、20)通过溶胶-凝胶法显示出小于200 nm的粒径。以性能最好的Li 1.2 Ni 0.3 Ti 0.3 Ti 0.3 Nb 0.2 O 2(平均电压约为2.7 V,高放电容量为221.5 mAh g –1)作为氧化物模型,我们通过X射线衍射(XRD),扫描电子显微镜,透射电子显微镜,X-射线衍射研究了阳离子无序氧化物的结构,形态,氧化还原机理和电化学性能之间的关系。射线光电子能谱,X射线吸收近边缘能谱测试以及电化学原位XRD。结果表明,提高的容量主要归因于Nb 5+,从而优化了Ni 2+ / Ni 4+的实际容量并有效地稳定了O 2– / O –氧化还原反应。结果强调,Li-Ni-Ti-Nb-O化合物是阳离子无序过渡金属氧化物材料家族中有希望的成员。