Thermodynamics and Na kinetics in P2-type oxygen redox Mn-Ni binary layered oxides manipulated via Li substitution

Park, Sung‐Joon; Lee, Jaewoon; Ko, In Hwan; Koo, Sojung; Song, Seok Hyun; Koo, Chanwoo; Yoon, Geon Hee; Jeon, Tae Yeol; Kim, Hyungsub; Kim, Duho; Yu, Seung Ho

doi:10.1016/j.ensm.2021.07.013

Cited by 26 publications

(14 citation statements)

References 39 publications

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“…Returning to P2‐type materials, in order to increase operation voltage and suppress voltage hysteresis, our group circumvented the low operation voltage of P2‐Na x [Zn y Mn 1− y ]O 2 by substituting half of Zn 2+ with Ni 2+ , resulting in a high average voltage of approximately 3.5 V on discharge. [ 34 ] P2‐Na 0.67 [Ni 0.33 Mn 4+ 0.67 ]O 2 [ 43–47 ] and P2‐Na 0.67 [Li 0.22 Mn 4+ 0.78 ]O 2 [ 14,17,18,29,30,36,39 ] are the most studied sodium layered materials. The former compound has high operation voltage and lower voltage hysteresis, while the P2‐O2 phase transformation with severe volume change is inevitable on charge, which leads to poor cycling performance.…”

Section: Introductionmentioning

confidence: 99%

Hysteresis‐Suppressed Reversible Oxygen‐Redox Cathodes for Sodium‐Ion Batteries

Voronina

Shin

Kim

et al. 2022

Advanced Energy Materials

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Oxygen‐redox‐based cathode materials for sodium‐ion batteries (SIBs) have attracted considerable attention in recent years owing to the possibility of delivering additional capacity in the high‐voltage region. However, they still suffer from not only fast capacity fading but also poor rate capability. Herein, P2‐Na0.75[Li0.15Ni0.15Mn0.7]O2 is introduced, an oxygen‐redox‐based layered oxide cathode material for SIBs. The effect of Ni doping on the electrochemical performance is investigated by comparison with Ni‐free P2‐Na0.67[Li0.22Mn0.78]O2. The Na0.75[Li0.15Ni0.15Mn0.7]O2 delivers a specific capacity of ≈160 mAh g−1 in the voltage region of 1.5–4.6 V at 0.1 C in Na cells. Combined experiments (galvanostatic cycling, neutron powder diffraction, X‐ray absorption spectroscopy, X‐ray photoelectron spectroscopy, and nuclear magnetic resonance (7Li NMR)) and theoretical studies (density functional theory calculations) confirm that Ni substitution not only increases the operating voltage and decreases voltage hysteresis but also improves the cycling stability by reducing Li migration from transition metal to Na layers. This research demonstrates the effect of Li and Ni co‐doping in P2‐type layered materials and suggests a new strategy of using Mn‐rich cathode materials via oxygen redox with optimization of doping elements for SIBs.

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Section: Introductionmentioning

confidence: 99%

Hysteresis‐Suppressed Reversible Oxygen‐Redox Cathodes for Sodium‐Ion Batteries

Voronina

Shin

Kim

et al. 2022

Advanced Energy Materials

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“…In sharp contrast, NMO-F delivered a much higher discharge capacity of 202 mA h g −1 (Figure 4d), which is among the best results of layered cathode materials reported in the literature. 18,20,23 In addition, better cycling performance was also obtained for NMO-F than for NMO-S. The NMO-F cathode retained a capacity of 146 mA h g −1 after 100 cycles at a current density of 100 mA g −1 (84%), compared with 98 mA h g −1 @80% for NMO-S, indicating that the P′2 phase has a better structural stability during the charge/discharge cycling (Figure 4c and Table S5).…”

Section: Resultsmentioning

confidence: 99%

“…11−15 Among various cathode materials, layered sodium manganese oxides (Na x MnO 2 ) have gained significant attention because of their high theoretical specific capacities. 16−19 Many preparation methods have been reported for layered Na x MnO 2 including the solid-state reaction, 20−22 sol−gel method, 19 coprecipitation, 23 hydrothermal synthesis, and so on. 24 However, all these methods require a long calcination process, leading to low productivity and waste of energy.…”

Section: Introductionmentioning

confidence: 99%

“…Sodium-ion batteries (SIBs), due to the low-cost and natural abundance of sodium compounds, have been regarded as a promising candidate for large-scale energy storage devices. − However, the energy density and cyclic stability of SIBs are insufficient for practical use, mainly limited by the unsatisfactory electrochemical performance of the cathode, caused by the huge volume change and sluggish kinetics due to the large ion radius. − Great efforts have been devoted to developing superior performance cathode materials with high energy density and good cycling stability. − Among various cathode materials, layered sodium manganese oxides (Na x MnO 2 ) have gained significant attention because of their high theoretical specific capacities. − Many preparation methods have been reported for layered Na x MnO 2 including the solid-state reaction, − sol–gel method, coprecipitation, hydrothermal synthesis, and so on . However, all these methods require a long calcination process, leading to low productivity and waste of energy.…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast Synthesis of Layered Transition-Metal Oxide Cathodes from Metal–Organic Frameworks for High-Capacity Sodium-Ion Batteries

et al. 2022

ACS Appl. Mater. Interfaces

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Layered transition-metal oxides are promising candidate cathode materials for sodium-ion batteries due to their abundant raw materials and high theoretical capacity. Nevertheless, a long-time high-temperature heat treatment is required in traditional preparation methods, leading to low synthesis efficiency and waste of energy. Herein, an ultrafast preparation method of layered transition-metal oxides was proposed through minute calcination of metal–organic frameworks (MOFs). The homogeneous distribution of different atoms in MOFs allows fast phase transition during the calcination process. P′2-phase layered sodium manganese oxide was successfully obtained and demonstrated excellent electrochemical performance, with a high reversible capacity of 212 mA h g–1 and a cycling performance of 84% capacity retention after 100 cycles. Furthermore, this method can be expanded to a wide variety of MOF precursors and oxide electrode materials for different types of batteries. Our findings provide an efficient and cost-effective synthesis method for high-performance layered transition-metal oxide cathodes.

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“…Given the importance of superstructure control, it was revealed in Li-excess 3 d Na oxides with R = 4 that the Li ions in the [Li 0.2 Mn 0.8 ]O 2 layer in the pristine state returned to their initial positions upon discharging after activating the first desodiation. In addition, similar nonhysteretic OR reactions during the first (de)sodiation were observed in different layered-type oxides that commonly contain Li ions in the TM layer. − In this regard, the excess Li ion in nonhysteretic Mn oxides for SIBs is essential to enable reversible oxygen capacities without large voltage hysteresis; however, its intrinsic role is not yet clearly understood. These considerations motivated a systematic understanding of the reaction mechanism of the O3-type Li-excess Mn oxide, Na[Li 1/3 Mn 2/3 ]O 2 (NLMO), that was designed as a pioneering OR cathode for advanced SIBs to determine generalized Li roles resulting in nonhysteretic oxygen capacities .…”

Section: Introductionmentioning

confidence: 91%

Physicochemical Screen Effect of Li Ions in Oxygen Redox Cathodes for Advanced Sodium-Ion Batteries

et al. 2022

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Unlike in lithium-ion batteries (LIBs), in sodiumion batteries (SIBs), nonhysteretic oxygen redox (OR) reactions are observed in Li-excess Na-layered oxides. This necessitates an understanding of the reaction mechanism of an O3-type Li-excess Mn oxide, Na[Li 1/3 Mn 2/3 ]O 2 , a novel OR material designed for advanced SIBs. It could establish the role of Li in triggering nonhysteretic oxygen capacities during (de)sodiation. Three biphasic mechanisms were compared using first-principles calculations under the desodiation modes: (i) Na/vacancy ordering, (ii) Li migration in the NaO 2 layer, and (iii) in-plane Mn migration. The migrated Li ions generated a "physicochemical screen" effect upon electrochemical OR reactions in the oxide cathode. Thermodynamic formation energies showed different biphasic pathways upon charging in Na 1−x [Li 2/6 Mn 4/6 ]O 2 (NLMO) under the three modes. O−O bond population indicated that biphasic-reaction paths -i and -iii were derived from generating inter/ intralayer O−O dimers, and path-iii was triggered by the formation of a Mn−O 2 −Mn moiety. However, Li migration exhibited an ideal OR process (O 2− /O n− ) without forming anionic dimers. The electronic structures of Mn(3d) and O(2p) revealed that Li migration pushed lattice-based O(2p)-hole states to a high energy level, resulting in the chemical suppression of O 2 molecule formation. Selectively decoupled oxygen ordering indicated that the oxygen species coordinated with two Mn (O Mn2 ) derived from Li migration played an important role in nonhysteretic oxygen capacities during cycling. From these findings, we propose the "physicochemical screen" concept that physically suppresses interlayer O−O dimers and chemically hinders discretized O(2p)− O(2p) states formed by molecular O 2 . This could significantly impact the role of Li ions in Li-excess OR-layered oxides for SIBs.

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Thermodynamics and Na kinetics in P2-type oxygen redox Mn-Ni binary layered oxides manipulated via Li substitution

Cited by 26 publications

References 39 publications

Hysteresis‐Suppressed Reversible Oxygen‐Redox Cathodes for Sodium‐Ion Batteries

Hysteresis‐Suppressed Reversible Oxygen‐Redox Cathodes for Sodium‐Ion Batteries

Ultrafast Synthesis of Layered Transition-Metal Oxide Cathodes from Metal–Organic Frameworks for High-Capacity Sodium-Ion Batteries

Physicochemical Screen Effect of Li Ions in Oxygen Redox Cathodes for Advanced Sodium-Ion Batteries

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