Is it universal that the layered-spinel structure can improve electrochemical performance?

Wang, Daqiang; Wu, Zhenguo; Xiang, Wei; Wang, Gongke; Hu, Kanghui; Xu, Qi; Song, Yang; Guo, Xiaodong

doi:10.1016/j.jechem.2021.04.030

Cited by 11 publications

(9 citation statements)

References 46 publications

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“…Recently, Li- and Mn-rich layered oxide (LMR) materials with the chemical composition of xLi 2 MnO 3 ·(1– x )LiMO 2 (M = Mn, Ni, Co) have attracted the attention of researchers because of their high capacity (250 mAh g –1 ) and low cost characteristics. − However, the disadvantages of LMR materials are obvious, such as large irreversible capacity and voltage attenuation, which hinder the further commercialization of LMR materials. , In the initial charge process, with the Li 2 MnO 3 component activated above 4.5 V, oxygen participates in the redox reaction, and the surface oxygen escapes in the form of O 2 , resulting in low initial Coulombic efficiency. − During the cycling process, the transition metal (TM) ions migrate to the Li layer, resulting in an irreversible phase transition from the layered to a spinel structure and then to a rock-salt structure. − In addition, the irreversible phase transition can also lead to voltage attenuation.…”

Section: Introductionmentioning

confidence: 99%

“…5−10 However, the disadvantages of LMR materials are obvious, such as large irreversible capacity and voltage attenuation, which hinder the further commercialization of LMR materials. 11,12 In the initial charge process, with the Li 2 MnO 3 component activated above 4.5 V, oxygen participates in the redox reaction, and the surface oxygen escapes in the form of O 2 , resulting in low initial Coulombic efficiency. 13−15 During the cycling process, the transition metal (TM) ions migrate to the Li layer, resulting in an irreversible phase transition from the layered to a spinel structure and then to a rock-salt structure.…”

Section: Introductionmentioning

confidence: 99%

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Highly Oriented {010} Crystal Plane Induced by Boron in Cobalt-Free Li- and Mn-Rich Layered Oxide

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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Li- and Mn-rich layered oxide (LMR) materials are a promising candidates for next-generation Li-ion battery (LIB) anode materials because of their high specific capacity. However, their low initial Coulombic efficiency, voltage decay, and irreversible phase transition during cycling are the fatal drawbacks of LMR materials. This work reports on a cobalt-free LMR material composed of primary particles with a boron-induced exposed long- strip-like {010} plane. Because of this unique structure, the long strip-like cathode exhibits excellent electrochemical performance with a discharge capacity of 202 mAh g–1 at 1 C and a retention rate of 95.2% after 200 cycles. In addition, it is found that this long strip-like structure can modulate the redox of oxygen and enhance the reversibility. The irreversible phase transition process from the layered to a spinel and then to a rock-salt phase during cycling is also significantly suppressed. This work provides a feasible method for regulating the exposed {010} plane and a new idea for the structural design of LMR materials.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Highly Oriented {010} Crystal Plane Induced by Boron in Cobalt-Free Li- and Mn-Rich Layered Oxide

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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“…The peak at 531.2 eV can be attributed to the existence of an oxygen vacancy. , The relative area of the peak is 11.6% in C–LOH and 18.4% in C–LCO, suggesting more structural defects when using Li 2 CO 3 as the lithium source. In addition, the peaks at a binding energy located at 654.5 and 642.8 eV could be assigned to Mn 2p3/2 and Mn 2p1/2 for Mn 4+ , as shown in Figure S2, indicating that the average chemical valence state of Mn of prepared LMLOs is close to +4 . The peaks at 872.6 and 855.0 eV could be assigned to Ni 2p1/2 and 2p3/2 for Ni 2+ , and the peaks at 874.6 and 857.0 eV could be attributed to 2p1/2 and 2p3/2 for Ni 3+ .…”

Section: Resultsmentioning

confidence: 88%

“…Many works have confirmed that some nonequilibrium intermediates during the high-temperature solid sintering process may act as templates for the final prepared phase transformation or even remain as impurities in final compounds. − It is reported that LiCoO 2 , LiNiO 2 , and Li x (Ni, Co)O 2 are prepared by acetate precursors, and their transformation intermediates are metastable spinel intermediates (Co 3 O 4 and Li 2 Co 2 O 4 ; Fd m ), rock-salts (Ni, Co)O, and disordered rock-salts (Li x (Ni, Co) 2– x O 2 ; Fm m ), respectively . In addition, our another work has revealed that increasing the nickel content in the precursor design can adjust the spinel phase in prepared LMLO cathode materials after sintering, thereby achieving an improvement in rate performance . When LiNi 0.6 Co 0.2 Mn 0.2 O 2 is prepared from Ni 0.6 Co 0.2 Mn 0.2 (OH) 2 or Ni 0.6 Co 0.2 Mn 0.2 CO 3 precursor, their reaction pathways all go through a disordered rock-salt phase (Li x (Ni 0.6 Co 0.2 Mn 0.2 ) 1– x , Fm m ) and a disordered layered off-stoichiometric phase (Li 1– x (Ni 0.6 Co 0.2 Mn 0.2 ) 1+ x O 2 , R m , x > 0.8).…”

Section: Introductionmentioning

confidence: 99%

“…39−46 41 In addition, our another work has revealed that increasing the nickel content in the precursor design can adjust the spinel phase in prepared LMLO cathode materials after sintering, thereby achieving an improvement in rate performance. 47 When LiNi 0.6 Co 0.2 Mn 0.2 O 2 is prepared from Ni 0.6 Co 0.2 Mn 0.2 (OH) 2 or Ni 0.6 Co 0.2 Mn 0.2 CO 3 precursor, their reaction pathways all go through a disordered rock-salt phase (Li x (Ni 0.6 Co 0.2 Mn 0.2 ) 1−x , Fm3m) and a disordered layered offstoichiometric phase (Li 1−x (Ni 0.6 Co 0.2 Mn 0.2 ) 1+x O 2 , R3m, x > 0.8). However, the transition temperature to a layered structure when using Ni 0.6 Co 0.2 Mn 0.2 (OH) 2 is lower than that when using Ni 0.6 Co 0.2 Mn 0.2 CO 3 .…”

Section: ■ Introductionmentioning

confidence: 99%

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New Insight into High-Rate Performance Lithium-Rich Cathode Synthesis through Controlling the Reaction Pathways by Low-Temperature Intermediates

Qiu

Wang

Chen

et al. 2021

Ind. Eng. Chem. Res.

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Li- and Mn-rich layered transition metal oxides (LMLOs) have attracted much attention because of their high theoretical capacities containing both transition metal cation and oxygen anion redox processes. However, the poor electrical conductivity and slow lithium-ion diffusion under high voltage result in an undesirable rate performance, which limits the commercial application of LMLOs. In this work, we found that the types of lithium source (including LiOH and Li2CO3) changed the intermediate transformation process, which in turn controlled the microstructure and morphology of LMLOs, thereby affecting the electrochemical performance. The prepared Li-rich cathode using LiOH as the lithium source accelerates the decomposition of the precursors. The structure undergoes rock-salt to disordered layered phase conversion and finally converts to an ordered layered structure. With Li2CO3 as the lithium source, the structure undergoes a spinel-layer intermediate transition process. The stable spinel phase is difficult to completely convert to a layered phase and remains in the final product. The LMLOs with spinel-layer composition exhibit an excellent rate performance of 178 mA h g–1 at 5 C, which is 39.1 mA h g–1 higher than that of LMLOs prepared by using LiOH as the lithium source. This insight into the preparation of high-performance materials by controlling the intermediate transformation provides a reference for the synthesis of advanced electrode materials through the reasonable selection of raw materials.

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Enabling Efficient Aerobic 5‐Hydroxymethylfurfural Oxidation to 2,5‐Furandicarboxylic Acid in Water by Interfacial Engineering Reinforced Cu−Mn Oxides Hollow Nanofiber

et al. 2022

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Herein, a one-dimensional hollow nanofiber catalyst composed of tightly packed multiphase metal oxides of Mn 2 O 3 and Cu 1.4 Mn 1.6 O 4 was constructed by electrospinning and tailored thermal treatment procedure. The characterization results comprehensively confirmed the special morphology and composition of various comparative catalysts. This strategy endowed the catalyst with abundant interfacial characteristics of components Mn 2 O 3 and Cu 1.4 Mn 1.6 O 4 nanocrystal. Impressively, the tuning thermal treatment resulted in tailored Cu I sites and surface oxygen species of the catalyst, thus affording optimized oxygen vacancies for reinforced oxygen adsorption, while the concomitant enhanced lattice oxygen activity in the constructed composite catalyst ensured the higher catalytic oxidation ability. More importantly, the regulated proportion of oxygen vacancy and lattice oxygen in the composite catalyst was obtained in the best catalyst, beneficial to accelerate the reaction cycle. Compared to other counterparts obtained by different temperatures, the CMO-500 sample exhibited superior selective aerobic 5-hydroxymethylfurfural (HMF) oxidation to 2,5-furandicarboxylic acid (FDCA, 96 % yield) in alkali-bearing aqueous solution using O 2 at 120 °C, which resulted from the above-mentioned composition optimization and interfacial engineering reinforced surface oxygen consumption and regeneration cycle. The reaction mechanism was further proposed to uncover the lattice oxygen and oxygen vacancy participating HMF conversion process.

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Is it universal that the layered-spinel structure can improve electrochemical performance?

Cited by 11 publications

References 46 publications

Highly Oriented {010} Crystal Plane Induced by Boron in Cobalt-Free Li- and Mn-Rich Layered Oxide

Highly Oriented {010} Crystal Plane Induced by Boron in Cobalt-Free Li- and Mn-Rich Layered Oxide

New Insight into High-Rate Performance Lithium-Rich Cathode Synthesis through Controlling the Reaction Pathways by Low-Temperature Intermediates

Enabling Efficient Aerobic 5‐Hydroxymethylfurfural Oxidation to 2,5‐Furandicarboxylic Acid in Water by Interfacial Engineering Reinforced Cu−Mn Oxides Hollow Nanofiber

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