000069756 001__ 69756
000069756 005__ 20190709135618.0
000069756 0247_ $$2doi$$a10.1039/c7ra04043a
000069756 0248_ $$2sideral$$a104788
000069756 037__ $$aART-2017-104788
000069756 041__ $$aeng
000069756 100__ $$aLudwig, J.
000069756 245__ $$aDirect synthesis and characterization of mixed-valent Li0.5-dCoPO4, a Li-deficient derivative of the Cmcm polymorph of LiCoPO4
000069756 260__ $$c2017
000069756 5060_ $$aAccess copy available to the general public$$fUnrestricted
000069756 5203_ $$aWhile the majority of research activities on LiCoPO4 is focussed on the thermodynamically stable olivine-type Pnma polymorph, the metastable Pna21 and Cmcm modifications have recently attracted considerable attention due to their interesting material properties. In this study, we present the first Li-deficient structural derivative of the Cmcm modification with the nominal composition Li0.5-dCoPO4. As opposed to the substoichiometric olivine (Pnma) phases LixCoPO4 (x = 0; 2/3), which are exclusively accessible by electrochemical or chemical Li extraction techniques, this is also the first time that a direct soft-chemical synthesis route towards a LixCoPO4-type material is accomplished. X-ray and neutron diffraction studies indicate that Cmcm-type Li0.5-dCoPO4 shows vacancies on both the Li and Co sites, whereas X-ray absorption spectra demonstrate that the structure features heterovalent Co ions (+2/+3) to compensate for the Li deficit. Magnetic measurements reveal a long-range antiferromagnetic order below 10.5 K. A thorough investigation of the thermal stability using thermogravimetric analysis, differential scanning calorimetry, and temperature-dependent in situ X-ray powder diffraction demonstrates that Li0.5-dCoPO4 is metastable and exhibits a complex, multi-step thermal decomposition mechanism. In the first step at 394 °C, it decomposes to a-Co2P2O7 (P21/c) and LiCoPO4 (Cmcm) upon O2 release. The LiCoPO4 (Cmcm) intermediate is then irreversibly transformed to olivine-type LiCoPO4 (Pnma) at 686 °C. The material properties of Li0.5-dCoPO4 are further compared to the fully lithiated, isostructural LiCoPO4 (Cmcm) phase, for which an improved structure solution as well as Co L2, 3-edge X-ray absorption spectra are reported for the first time.
000069756 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc$$uhttp://creativecommons.org/licenses/by-nc/3.0/es/
000069756 590__ $$a2.936$$b2017
000069756 591__ $$aCHEMISTRY, MULTIDISCIPLINARY$$b71 / 171 = 0.415$$c2017$$dQ2$$eT2
000069756 592__ $$a0.863$$b2017
000069756 593__ $$aChemistry (miscellaneous)$$c2017$$dQ1
000069756 593__ $$aChemical Engineering (miscellaneous)$$c2017$$dQ1
000069756 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000069756 700__ $$aAlarcón-Suesca, C.
000069756 700__ $$aGeprägs, S.
000069756 700__ $$aNordlund, D.
000069756 700__ $$aDoeff, M.M.
000069756 700__ $$0(orcid)0000-0001-8224-329X$$aPuente Orench, I.
000069756 700__ $$aNilges, T.
000069756 773__ $$g7, 45 (2017), 28069-28081$$pRSC ADVANCES$$tRSC Advances$$x2046-2069
000069756 8564_ $$s495281$$uhttps://zaguan.unizar.es/record/69756/files/texto_completo.pdf$$yVersión publicada
000069756 8564_ $$s107722$$uhttps://zaguan.unizar.es/record/69756/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000069756 909CO $$ooai:zaguan.unizar.es:69756$$particulos$$pdriver
000069756 951__ $$a2019-07-09-12:26:26
000069756 980__ $$aARTICLE