Enhanced thermopower in an intergrowth cobalt oxide Li0.48Na0.35CoO2

Ren, Zhi; Shen, Jingqin; Jiang, Shuai; Chen, Xiaoyang; Feng, Chunmu; Xu, Z. A.; Cao, Guanghan

doi:10.1088/0953-8984/18/29/l01

Cited by 25 publications

(38 citation statements)

References 28 publications

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“…6,12,13 The composition obtained by ICP-AES is close to Li ϳ0.45 Na ϳ0.39 CoO 2 . A detailed characterization of this material either for structural or physical point of view will be reported in a forthcoming paper.…”

Section: Resultsmentioning

confidence: 59%

Synthesis and Investigations on an O4-LiCoO[sub 2] Polytype

Berthelot

Carlier

Pollet

et al. 2009

Electrochem. Solid-State Lett.

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A polytype of LiCoO 2 has been synthesized through an ion-exchange reaction. By exchanging Na + for Li + ions from an OP4-͑Li/Na͒CoO 2 -mixed cobaltite, a LiCoO 2 stacking is obtained. It alternatively combines O2-and O3-LiCoO 2 polytypes and corresponds to an O4 stacking. The phase crystallizes in the hexagonal system with cell parameters a hex = 2.802͑1͒ Å and c hex = 18.89͑2͒ Å. As the O2 phase, the O4-LiCoO 2 , is metastable; it transforms into the thermodynamically stable O3-LiCoO 2 at around 350-400°C. The crystallographic data, the thermal properties, and the electrochemical behavior of this phase are presented.LiCoO 2 is widely used as a positive electrode material in most of the commercialized lithium-ion batteries. Its structure consists of a stacking of CoO 2 layers of edge-sharing CoO 6 octahedra between which lithium ions are inserted in octahedral sites. Two lamellar LiCoO 2 polytypes with O3 and O2 types of oxygen packing ͑see Ref. 1 for the nomenclature͒ are already known and differ by their slab stacking sequence along the c axis ͑Fig. 1͒. The O3 polytype is obtained by a high temperature solid-state reaction. 2 It is the thermodynamically stable variety as the LiO 6 and CoO 6 octahedra share only edges. The O2 polytype is obtained by an ion-exchange from P2-Na ϳ0.7 CoO 2 . 3 During the Na + /Li + exchange, the Li + ions are too small to occupy trigonal prismatic sites and therefore, a gliding of the CoO 2 slab occurs that fixes the octahedral surrounding of the Li + ions. In this structure, the LiO 6 octahedra share one face with one CoO 6 octahedron and three edges with different CoO 6 octahedra on the opposite side. As a result, this face sharing the O2 phase is metastable and transforms into the thermodynamically stable O3 polytype between 100 and 150°C. 4,5 In 1994, Balsys and Davis 6 reported the synthesis and the structure description of a lithium/sodium-mixed cobaltite Li 0.43 Na 0.39 CoO 1.96 . Its structure consists of CoO 2 slabs with an alternate sequence of LiO 6 octahedra and NaO 6 trigonal prisms, leading to an OP4-type oxygen packing that agrees with the nomenclature in Ref. 1. Starting with this phase and using chemical exchange reaction like in the P2-Na ϳ0.7 CoO 2 → O2-LiCoO 2 transformation, we were successful in preparing a LiCoO 2 polytype that keeps the original alternation of the alkali layers initially present in the OP4-͑Li/Na͒CoO 2 phase: the leads to an alternate staking of O3 and O2-LiCoO 2 polytypes in a fully single phase: the O4-LiCoO 2 polytype. This article describes the synthesis of this stacking, the phase stability, and a preliminary electrochemical study. ExperimentalOP4-͑Li/Na͒CoO 2 precursor.-O3-LiCoO 2 and P2-Na ϳ0.7 CoO 2 phases were obtained by high temperature solid-state reaction as previously described. 2,7,8 A mixture of these two compounds corresponding to the Li 0.42 Na 0.41 CoO 2 nominal composition was intimately ground and then heated into a sealed gold tube for 15 h at ca. 920°C in a preheated furnace. After the reaction, the tube was quenched ...

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Section: Resultsmentioning

confidence: 59%

Synthesis and Investigations on an O4-LiCoO[sub 2] Polytype

Berthelot

Carlier

Pollet

et al. 2009

Electrochem. Solid-State Lett.

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“…The occurrence of both Li + and Na + occur in the interlayer space can be understood taking into account the available crystallographic data in the literature. In this aspect, mixed sodium lithium cobalt oxides, Li ∼0.42 Na ∼0.37 CoO 2 , represents a classical example for structure integration of two distinct blocks: a P2 ‐type sodium block and an O3 ‐type lithium one . Contrary to Li ∼0.42 Na ∼0.37 CoO 2 , a randomly distributed sodium and lithium ions in the lithium layers, has only been detected in the early stage of ion exchange of Na + with Li + in O3 ‐NaNi 0.5 Mn 0.5 O 2 .…”

Section: Structural Matrices Suitable For Li+ Na+ and Mg2+ Intercalamentioning

confidence: 99%

Lithium versus Mono/Polyvalent Ion Intercalation: Hybrid Metal Ion Systems for Energy Storage

Stoyanova

Koleva

2018

The Chemical Record

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The energy storage by redox intercalation reactions is, nowadays, the most effective rechargeable ion battery. When lithium is used as intercalating agents, the high energy density is achieved at an expense of non-sustainability. The replacement of Li with cheaper monovalent ions enables to make greener battery alternatives. The utilization of polyvalent ions instead of Li permits to multiplying the battery capacity. Contrary to Li , the realization of quick and reversible intercalation of bigger monovalent and of polyvalent ions is a scientific challenge due to kinetic constraints, polarizing ion effects and Coulomb interactions. Herein we provide a vision how to make the intercalation of these ions feasible. The idea is to perform dual intercalation of ions having different charges, radii, preferred coordination and diffusion pathway topology. All these features are demonstrated by the recent knowledge on selective and non-selective intercalation properties of oxides and polyanion compounds with layered and tunnel structures. Based on dual intercalation properties, the fabrication of hybrid metal ion batteries is presented and discussed.

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“…By using O3-LiCoO2 and P2-Na0.7CoO2 as precursors for their synthesis, Balsys and Davis indicated the difficulty to obtain a pure phase. Additional publications propose the synthesis of this phase without any consensus concerning the best precursors or thermal treatment to obtain the purest phase [15][16][17][18][19][20][21] . Table in proposed chemical formulas differ from the ideal Li0.5Na0.35CoO2 one, but the presence of traces of O3-LiCoO2 and P2-Na0.7CoO2 as impurities may alter the composition determined by Inductively Coupled Plasma (ICP) measurements 17 .…”

Section: Introductionmentioning

confidence: 99%

Original Layered OP4-(Li,Na)_xCoO₂ Phase: Insights on Its Structure, Electronic Structure, and Dynamics from Solid State NMR

et al. 2020

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The OP4-(Li/Na)xCoO2 phase is an unusual lamellar oxide with a 1:1 alternation between Li and Na interslab spaces. In order to probe the local structure, electronic structure and dynamics, 7 Li and 23 Na magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy were performed in complementarity to X-ray diffraction and electronic and magnetic properties measurements. 7 Li MAS NMR showed that NMR shifts result from two contributions: the Fermi contact and the Knight shifts due to the presence of both localized and delocalized electrons that is really unusual. 7 Li MAS NMR clearly shows several Li environments indicating that, moreover, Co ions with different local electronic structures are formed, probably due to the arrangement of the Na + ions in the next cationic layer. 23 Na MAS NMR showed that some Na + ions are located in the Li layer what was not previously considered in the structural model. The Rietveld refinement of the synchrotron XRD led to the OP4-[Li0.42Na0.05]Na0.32CoO2 formula for the material. In addition, 7 Li and 23 Na MAS NMR provide information about the cationic mobility in the material: whereas no exchange is observed for 7 Li up to 450K, the 23 Na spectra reveals already a single average signal at room temperature due to much larger ionic mobility.

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Enhanced thermopower in an intergrowth cobalt oxide Li_0.48Na_0.35CoO₂

Cited by 25 publications

References 28 publications

Synthesis and Investigations on an O4-LiCoO[sub 2] Polytype

Synthesis and Investigations on an O4-LiCoO[sub 2] Polytype

Lithium versus Mono/Polyvalent Ion Intercalation: Hybrid Metal Ion Systems for Energy Storage

Original Layered OP4-(Li,Na)_xCoO₂ Phase: Insights on Its Structure, Electronic Structure, and Dynamics from Solid State NMR

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Enhanced thermopower in an intergrowth cobalt oxide Li0.48Na0.35CoO2

Cited by 25 publications

References 28 publications

Synthesis and Investigations on an O4-LiCoO[sub 2] Polytype

Synthesis and Investigations on an O4-LiCoO[sub 2] Polytype

Lithium versus Mono/Polyvalent Ion Intercalation: Hybrid Metal Ion Systems for Energy Storage

Original Layered OP4-(Li,Na)xCoO2 Phase: Insights on Its Structure, Electronic Structure, and Dynamics from Solid State NMR

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Enhanced thermopower in an intergrowth cobalt oxide Li_0.48Na_0.35CoO₂

Original Layered OP4-(Li,Na)_xCoO₂ Phase: Insights on Its Structure, Electronic Structure, and Dynamics from Solid State NMR