气候变化领域集成服务门户(CCPortal): High voltage structural evolution and enhanced Na-ion diffusion in P2-Na2/3Ni1/3-: XMgxMn2/3O2 (0 ≤ x ≤ 0.2) cathodes from diffraction, electrochemical and ab initio studies

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DOI	10.1039/c7ee02995k
	High voltage structural evolution and enhanced Na-ion diffusion in P2-Na2/3Ni1/3-: XMgxMn2/3O2 (0 ≤ x ≤ 0.2) cathodes from diffraction, electrochemical and ab initio studies
	Tapia-Ruiz N.; Dose W.M.; Sharma N.; Chen H.; Heath J.; Somerville J.W.; Maitra U.; Islam M.S.; Bruce P.G.
发表日期	2018
ISSN	17545692
起始页码	1470
结束页码	1479
卷号	11 期号:6
英文摘要	We have presented a detailed investigation of the effects of Mg substitution on the structure, electrochemical performance and Na-ion diffusion in high voltage P2-type Na2/3Ni1/3-xMgxMn2/3O2 (0 < x < 0.2) cathode materials for Na-ion batteries. Structural analysis using neutron diffraction showed that Mg2+ substitutes at Ni2+ sites from ordered [(Ni2+/Mn4+)O6] honeycomb units along the ab-plane, leading to an AB-type structure that can be indexed using the P63 space group. Within the sodium layers, high Mg-substitution levels (i.e. x = 0.2) caused a disruption in the typical Na zig-zag ordering observed in the undoped material, leading to a more disordered Na distribution in the layers. Load curves of the x = 0.1 and 0.2 materials show smooth electrochemistry, indicative of a solid-solution process. Furthermore, DFT calculations showed an increase in Na-ion diffusivity for the Mg-substituted samples. Enhanced cycling stability was also observed in these materials; structural analysis using high-resolution in operando synchrotron X-ray diffraction show that such an improved electrochemical performance is caused by the suppression of the O2 phase and switch to the formation of an OP4 phase. Ab initio studies support our experimental evidence showing that the OP4 phase (cf. O2) is the most thermodynamically stable phase at high voltages for Mg-substituted compounds. Finally, we have provided evidence using diffraction for the x = 1/2 and x = 1/3 intermediate Na+-vacancy ordered phases in P2-Na2/3Ni1/3Mn2/3O2. © 2018 The Royal Society of Chemistry.
英文关键词	Calculations; Cathodes; Electrochemistry; Ions; Neutron diffraction; Structural analysis; Cath-ode materials; Electrochemical performance; Experimental evidence; Solid solution process; Structural evolution; Substituted compounds; Synchrotron x ray diffraction; Thermodynamically stable; Magnesium compounds; cation; diffusion; electric field; electrode; ion; magnesium; manganese oxide; neutron diffraction; sodium; structural analysis; substitution; X-ray diffraction
语种	英语
来源期刊	Energy & Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/190220
作者单位	Department of Materials and Chemistry, University of Oxford, Parks Road, Oxford, OX1 3PH, United Kingdom; School of Chemistry, UNSW Australia, Sydney, 2052, Australia; Department of Chemistry, University of Bath, Bath, BA2 7AY, United Kingdom
推荐引用方式 GB/T 7714	Tapia-Ruiz N.,Dose W.M.,Sharma N.,et al. High voltage structural evolution and enhanced Na-ion diffusion in P2-Na2/3Ni1/3-: XMgxMn2/3O2 (0 ≤ x ≤ 0.2) cathodes from diffraction, electrochemical and ab initio studies[J],2018,11(6).
APA	Tapia-Ruiz N..,Dose W.M..,Sharma N..,Chen H..,Heath J..,...&Bruce P.G..(2018).High voltage structural evolution and enhanced Na-ion diffusion in P2-Na2/3Ni1/3-: XMgxMn2/3O2 (0 ≤ x ≤ 0.2) cathodes from diffraction, electrochemical and ab initio studies.Energy & Environmental Science,11(6).
MLA	Tapia-Ruiz N.,et al."High voltage structural evolution and enhanced Na-ion diffusion in P2-Na2/3Ni1/3-: XMgxMn2/3O2 (0 ≤ x ≤ 0.2) cathodes from diffraction, electrochemical and ab initio studies".Energy & Environmental Science 11.6(2018).