Utilizing Co2+/Co3+ Redox Couple in P2‐Layered Na0.66Co0.22Mn0.44Ti0.34O2 Cathode for Sodium‐Ion Batteries

Wang, Qin‐Chao; Hu, Enyuan; Pan, Yang; Xiao, Na; Hong, Fan; Fu, Zheng‐Wen; Wu, Xiaojing; Bak, Seong‐Min; Yang, Xiao‐Qing; Zhou, Yong‐Ning

doi:10.1002/advs.201700219

Cited by 89 publications

(15 citation statements)

References 45 publications

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“…investigated the Co 2+ /Co 3+ redox couple in P2‐type Na 0.66 Co 0.22 Mn 0.44 Ti 0.34 O 2 . With the increasing Co contents from x=0 to 0.33 in Na 0.66 Co x Mn 0.66‐x Ti 0.34 O 2 , the crystal structure tends to transform from orthorhombic to hexagonal . From the XANES spectra, the low valence of Co 2+ substitution can favour Mn in the high valence state of +4, which will reduce the distortion of the Jahn‐Teller effect of Mn 3+ .…”

Section: Xas Techniques For Sodium Layered Transition Metal Oxidesmentioning

confidence: 99%

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Understanding Challenges of Cathode Materials for Sodium‐Ion Batteries using Synchrotron‐Based X‐Ray Absorption Spectroscopy

Chen

Chou

Dou

2019

Batteries & Supercaps

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An in-depth understanding of the electrochemical behavior of cathode materials in a complex chemical environment is critical for the development of state-of-the-art sodium-ion batteries. Advanced synchrotron-based characterization is a powerful tool for collecting valuable information on complicated reaction mechanisms. X-ray absorption spectroscopy can be used to precisely monitor the valence state and corresponding changes during cycling of various elements. Information on the local structure, such as coordination number and bond information can also be extracted from the fitting data in Fourier transform extended X-ray absorption fine structure. In this review, we summarize findings on state-of-the-art cathode materials using ex-situ/in-situ X-ray absorption spectroscopy to probe fundamental discoveries on sodium-ion battery systems and what important and valuable results have been obtained. Further possible improvements and practical operating advice are also discussed in detail. . (a) Crystal structure of Na 3 V 2 (PO 4 ) 2 F 3 with space group Amam. (b) V K-edge XANES spectra at C/10. Reprinted with permission from (a) to (b). [51] Copyright 2017American Chemical Society. (c) Crystal structure of ɛ-VOPO 4 and corresponding charge/discharge curve. V K-edge in-situ XAS spectra of Mo 0.05 V 0.95 OPO 4 for (d) high-voltage discharge and (e) low-voltage discharge.

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Section: Xas Techniques For Sodium Layered Transition Metal Oxidesmentioning

confidence: 99%

Section: Xas Techniques For Sodium Layered Transition Metal Oxidesmentioning

confidence: 99%

Understanding Challenges of Cathode Materials for Sodium‐Ion Batteries using Synchrotron‐Based X‐Ray Absorption Spectroscopy

Chen

Chou

Dou

2019

Batteries & Supercaps

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“…In 2017, a series of Na 0.66 Co x Mn 0.66− x Ti 0.34 O 2 materials with different structures were reported . These materials show a typical tunnel‐type structure when x = 0 (Na 0.66 Mn 0.66 Ti 0.34 O 2 ) and gradually become P2‐type structures when x = 0.22 (Na 0.66 Co 0.22 Mn 0.44 Ti 0.34 O 2 ).…”

Section: Classification Of Csmsmentioning

confidence: 99%

“…These materials show a typical tunnel‐type structure when x = 0 (Na 0.66 Mn 0.66 Ti 0.34 O 2 ) and gradually become P2‐type structures when x = 0.22 (Na 0.66 Co 0.22 Mn 0.44 Ti 0.34 O 2 ). Obviously, P2‐type and tunnel‐type hybrid structures can be observed when x = 0.11 (Na 0.66 Co 0.11 Mn 0.55 Ti 0.34 O 2 ) . However, the electrochemical performance of such P2‐type and tunnel‐type CSMs still needs further improvement.…”

Section: Classification Of Csmsmentioning

confidence: 99%

Composite‐Structure Materials for Na‐Ion Batteries

2018

Small Methods

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structure materials, [25][26][27][28][29][30][31][32][33] polyanion-based materials, [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] alloying materials, [9,[51][52][53][54][55][56] and Prussian blue analogs. [57][58][59][60][61] However, most of these developed materials are classified as single crystalline structures and exhibit limited electrochemical performances. Thus, scientists have started to think about developing a new material system that possesses the advantages of multiple materials in one material. An attractive strategy to accomplish this goal is the composite-structure material system, which has received much attention recently. [62][63][64] Compared with single-structure materials, compositestructure materials (CSMs) always exhibit better comprehensive electrochemical performance, e.g., larger reversible capacities and better cycling or rate performance. [65,66] The best example of a CSM has been studied in LIBs for many years, i.e., lithium-manganese-rich layered oxides (LLOs), [67][68][69][70] which possess both layered rhombohedral structures and mono clinic Li 2 MnO 3 -like structures. These CSMs deliver a high discharge capacity of ≈300 mAh g −1 and a high energy density of ≈1000 Wh kg −1 , which are almost two times larger than those of conventional cathode materials for LIBs.Electrode materials for NIBs are mostly derived from LIBs. Recently, some CSMs have been proposed to create NIBs with high electrochemical performance, exhibiting great potential in high-energy-density devices. However, most published CSMs are identified after the synthesis process, and few studies have been conducted on designing CSMs because of the complexity of their crystalline structure. In addition, characterizing all the structures in CSMs is more difficult than characterizing singlestructure materials. Currently, adjusting structural proportions and further balancing the electrochemical performance of CSMs still remain major challenges. Examining the literature, a detailed review of CSMs used in NIBs is lacking. In this work, research development of CSMs for NIBs is conducted based on the crystalline structure, including structure design, identification, and adjustment. Some important work and recent achievements on CSMs with a future outlook based on a mechanism analysis are also reviewed. By reviewing previous important studies on CSMs, a new electrode-material structure system for NIBs is established in this work. Structures in CSMsMost NIB electrode materials are developed based on LIB materials because the batteries have similar mechanisms. [1,3,4] Due to the growing concern of aggravated environmental problems (air pollution, global warming, etc.) and Li resources, Na-ion batteries have received significant attention as a promising alternative. Many electrode materials for Na-ion batteries have been reported in the past, especially over the past five years. However, most of these materials have a single crystalline structure and exhibit a limited electrochemical performance. Recently,...

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“…The high‐performance cathode materials of sodium‐ion batteries have been widely studied, including layered oxides, Prussian blue analogues and polyanion materials . Owing to simple manufacturing methods and reversible insertion/extraction, layered oxide Na x MeO 2 (Me = 3d transition metal, such as Co, Mn, Ni, Ti, Cu) materials are considered as one of the most promising candidates. Specifically, layered oxides can be mainly classified into two different types: P2‐type and O3‐type, in accordance with the coordination of sodium ions in the layered structure and the oxygen stacking sequence.…”

mentioning

confidence: 99%

Revealing the Critical Role of Titanium in Layered Manganese‐Based Oxides toward Advanced Sodium‐Ion Batteries via a Combined Experimental and Theoretical Study

et al. 2018

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interest on accounts of its low cost and abundance of sodium resource. [3][4][5] Additionally, the replacement of Cu with Al as the anode current collector can further reduce the cost and simplify the manufacturing process. [6] The high-performance cathode materials of sodium-ion batteries have been widely studied, [7] including layered oxides, [8,9] Prussian blue analogues [10,11] and polyanion materials. [12,13] Owing to simple manufacturing methods and reversible insertion/extraction, layered oxide Na x MeO 2 (Me = 3d transition metal, such as Co, Mn, Ni, Ti, Cu) [14][15][16][17][18] materials are considered as one of the most promising candidates. Specifically, layered oxides can be mainly classified into two different types: P2-type and O3-type, in accordance with the coordination of sodium ions in the layered structure and the oxygen stacking sequence. In contrast to O3-type, P2-type exhibits more open framework and direct Na-ion diffusion path associated with superior rate and cycling performance for sodium storage. [19][20][21] Manganese-based materials meet the demands for relatively cheap electrodes and different oxidation states of manganese make the voltage ranges flexible. [6] Additionally, as previously reported, the high electrochemical activity of layered manganese oxides has been demonstrated by the primitive test in 1980s. Therefore, the layered P2-type manganese-based oxide materials can be the appealing candidate as cathodes of sodium-ion batteries.However, owing to the Jahn-Teller active Mn 3+ ions followed by the dissolution of Mn ions into the electrolyte, the electrochemical performance of manganese-based oxides should be further improved via effectively suppressing the Jahn-Teller effect. [22,23] Many researchers tried various methods to optimize the composition of electrodes to improve the cyclic stability and rate performance, consisting of (1) surface coating, [22,24] and (2) substitution with some inactive elements. [25,26] Local atomic environment can be changed by doping with some inactive elements to improve the electrochemical performance, such as Mg, [25] Al, [26] etc. However, up to now, a general strategy toward robust sodium storage performance in layered Mn-based cathodes is still insufficient. In this work, we propose a strategy of Sodium-ion batteries are one of the most promising candidates for largescale energy storage. Manganese-based layered oxides are extensively studied as a cathode of sodium-ion batteries due to the low cost and high electrochemical activity. However, these layered cathodes usually suffer from the severe manganese dissolution originated from Jahn-Teller distortion, thereby leading to severe capacity fading and structural deterioration. Herein, it is demonstrated via a combined experimental and theoretical study, titanium substitution in layered manganese-based oxides can weaken the Jahn-Teller effect, minimize the relative dissolution, and thus enable robust sodium storage during long-term operation. Results reveal that Ti-doping can restrain shrinka...

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Utilizing Co²⁺/Co³⁺ Redox Couple in P2‐Layered Na_0.66Co_0.22Mn_0.44Ti_0.34O₂ Cathode for Sodium‐Ion Batteries

Cited by 89 publications

References 45 publications

Understanding Challenges of Cathode Materials for Sodium‐Ion Batteries using Synchrotron‐Based X‐Ray Absorption Spectroscopy

Understanding Challenges of Cathode Materials for Sodium‐Ion Batteries using Synchrotron‐Based X‐Ray Absorption Spectroscopy

Composite‐Structure Materials for Na‐Ion Batteries

Revealing the Critical Role of Titanium in Layered Manganese‐Based Oxides toward Advanced Sodium‐Ion Batteries via a Combined Experimental and Theoretical Study

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