Design and Synthesis of Layered Na2Ti3O7 and Tunnel Na2Ti6O13 Hybrid Structures with Enhanced Electrochemical Behavior for Sodium‐Ion Batteries

Wu, Chunjin; Hua, Weibo; Zhang, Zheng; Zhong, Benhe; Yang, Zuguang; Feng, Guilin; Xiang, Wei; Wu, Zhenguo; Guo, Xiaodong

doi:10.1002/advs.201800519

Cited by 112 publications

(87 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To explore the variation of the intrinsic properties of NTO before and after P doping, DFT calculations were conducted. NTO has a monoclinic crystal structure in space group P 21/ m consisting of layers of edge‐sharing and corner‐sharing [TiO 6 ] octahedra (Figure a), and the Na ions are located between the layers with 9‐(Na1) or 7‐(Na2) coordinated to nearby oxygen atoms . The calculated lattice constants are a =8.42, b =3.81, and c =9.08 Å, which are in very good agreement with experimental studies and other theoretical data .…”

Section: Resultssupporting

confidence: 78%

“…NTO has am onoclinic crystal structure in space group P21/m consisting of layers of edge-sharing and corner-sharing [TiO 6 ] octahedra (Figure 6a), and the Na ions are located between the layers with 9-(Na1) or 7-(Na2) coordinated to nearby oxygen atoms. [46,47] The calculated lattice constants are a = 8.42, b = 3.81, and c = 9.08 ,w hich are in very good agreement with experimental studies and other theoretical data. [48,49] The projected density of states (PDOS) of NTO near the Fermi energy level (Figure 6b)d emonstrates semiconductor characteristics with ab and gap of 3.23 .T he valence band maximum and conduction band minimum are mainly composed of O2 pa nd Ti 3d orbitals (in this case, the Fermi energy level was set to zero).…”

Section: Full Papersupporting

confidence: 81%

See 1 more Smart Citation

Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na₂Ti₃O₇ Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage

Liu

Jin

Huang

et al. 2019

Chemistry A European J

View full text Add to dashboard Cite

Sodium‐ion batteries have attracted interest as an alternative to lithium‐ion batteries because of the abundance and cost effectiveness of sodium. However, suitable anode materials with high‐rate and stable cycling performance are still needed to promote their practical application. Herein, three‐dimensional Na2Ti3O7 nanowire arrays with enriched surface vacancies endowed by phosphorus doping are reported. As anodes for sodium‐ion batteries, they deliver a high specific capacity of 290 mA h g−1at 0.2 C, good rate capability (50 mA h g−1at 20 C), and stable cycling capability (98 % capacity retention over 3100 cycles at 20 C). The superior electrochemical performance is attributed to the synergistic effects of the nanowire arrays and phosphorus doping. The rational structure can provide convenient channels to facilitate ion/electron transport and improve the capacitive contributions. Moreover, the phosphorus‐doping‐induced surface vacancies not only provide more active sites but also improve the intrinsic electrical conductivity of Na2Ti3O7, which will enable electrode materials with excellent sodium storage performance. This work may provide an effective strategy for the synthesis of other anode materials with fast electrochemical reaction kinetics and good sodium storage performance.

show abstract

Section: Resultssupporting

confidence: 78%

Section: Full Papersupporting

confidence: 81%

Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na₂Ti₃O₇ Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage

Liu

Jin

Huang

et al. 2019

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…For bulk degradations, irreversible bulk phase transition and cracking are the two main failure mechanisms. This work not only deepens the understanding on dopant evolution but also offers a conceptually new approach by utilizing precipitation strengthening design to counter cracking related degradation and improve highvoltage cyclability of layered cathodes.Layer structured alkali transition metal oxides are an important group of cathode materials for lithium ion batteries (LIBs), [1][2][3] sodium ion batteries (SIBs), [4][5][6] and potassium ion batteries A direct correlation between phase transition and cracking has been established in the P2 layered cathode for SIBs.…”

mentioning

confidence: 99%

“…Layer structured alkali transition metal oxides are an important group of cathode materials for lithium ion batteries (LIBs), [1][2][3] sodium ion batteries (SIBs), [4][5][6] and potassium ion batteries…”

mentioning

confidence: 99%

Dopant Segregation Boosting High‐Voltage Cyclability of Layered Cathode for Sodium Ion Batteries

et al. 2019

View full text Add to dashboard Cite

PIBs). [7,8] Either in the form of O3 structure, P2 structure or other else structures, their common similarity is the layer by layer stacking sequence of transition metal ions, oxygen ions, and alkaline ions. [9,10] Such a layered structure not only enables high-specific capacity but also favors the fast migration of alkaline ions due to the unique 2D diffusion pathway. Thus, layer structured LiCoO 2 , ternary NMC (LiNi x Mn y Co z O 2 , x + y + z = 1), and NCA (LiNi 0.85 Co 0.1 Al 0.05 O 2 ) have achieved great commercial success as high-performance cathode materials for LIBs. [11][12][13] Other layered cathode materials, such as Ni-rich NMC for LIBs [14,15] and Na-NMC layered cathodes for SIBs, are gaining increasing attentions. [12,16,17] One of the primary efforts on layered cathodes is further unlocking its capacity potential by narrowing the gap between the practical capacity and theoretical capacity. However, increasing the utilization of alkaline ions, usually by elevating the high-charge cutoff voltage, results in structural instability of the layered cathodes, due to aggravated surface/ interface chemical degradations and bulk degradations. [18][19][20] The surface/interface degradations are attributed to the chemical reactions between cathode and electrolyte, which leads to cathode surface phase transition, [21,22] active material dissolution, [23] passivation layer formation, [24] electrolyte consumption, [25] and so on. For bulk degradations, irreversible bulk phase transition and cracking are the two main failure mechanisms. At high state of charge, phase transition not only destructs the active layered structure but also introduces substantial volume changes causing mechanical failures. A direct correlation between phase transition and cracking has been established in the P2 layered cathode for SIBs. [26] Cleavage along layered planes leads to the typical intragranular cracking for many layered cathodes, which has been frequently observed after high-voltage cycling. [26][27][28] The detrimental effects of cracking include fracture caused disintegration, [28] which leads to poor electronic conduction [29,30] and loss of active materials, and new surfaces exposure to electrolyte which results in cathode surface degradation [31][32][33] and electrolyte consumption. In addition, high density of intragranular cracks also plagues battery thermal stability and safety. [27] Doping electrochemically inactive elements has been verified as an effective method to improve the electrochemical performance of layered cathodes. [34,35] Dopants can play multiroles in engineering bulk material, such as eliminating unwanted As a widely used approach to modify a material's bulk properties, doping can effectively improve electrochemical properties and structural stability of various cathodes for rechargeable batteries, which usually empirically favors a uniform distribution of dopants. It is reported that dopant aggregation effectively boosts the cyclability of a Mg-doped P2-type layered cathode (Na 0.67 Ni 0.33 Mn 0.6...

show abstract

“…The development of low cost and high performance cathodes play a key role in the commercialization process of SIBs . The composite cathodes have been intensively demonstrated with the advantages of integrated high performance via bi‐phasic synergistic effect …”

Section: Introductionmentioning

confidence: 99%

Simultaneous Component Ratio and Particle Size Optimization for High‐Performance and High Tap Density P2/P3 Composite Cathode of Sodium‐Ion Batteries

et al. 2019

Self Cite

View full text Add to dashboard Cite

The composite structure materials in sodium-ion batteries (SIBs) have received increasing attentions due to the synergistic effect. P2/P3 composite cathode with the advantages of high reversible capacity and superior reaction kinetics was regarded as one of the promising cathodes for SIBs. Crystal phase component ratio and particle morphology of hybrid structures are closely related with the electrochemical performance, especially the energy density. Herein, P2/P3 hybrid structure materials Na 0.6 Mn 1-x Ni x O 2 were synthesized by co-precipitation method. Furthermore, the component ratio and particle size are tuned and realized via simple Ni 2 + content optimization. The targeted sample Na 0.6 Mn 0.75 Ni 0.25 O 2 shows high tap density over 1.2 g cm À 3 and excellent electrical properties with an initial capacity of 101.36 mA h g À 1 at 0.2 C, corresponding to a high volumetric energy density of 512 Wh L À 1 based on the cathode active material. Moreover, the long-term cycling capacity retention can reach 68 % at 1 C after 500 cycles. The present study develops a promising cathode of SIBs that maybe applied in low-speed electric vehicles. And the simultaneous optimization design represents a potential route for the regulation of composite structures to obtain high performance SIBs.

show abstract

Design and Synthesis of Layered Na₂Ti₃O₇ and Tunnel Na₂Ti₆O₁₃ Hybrid Structures with Enhanced Electrochemical Behavior for Sodium‐Ion Batteries

Cited by 112 publications

References 44 publications

Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na₂Ti₃O₇ Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage

Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na₂Ti₃O₇ Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage

Dopant Segregation Boosting High‐Voltage Cyclability of Layered Cathode for Sodium Ion Batteries

Simultaneous Component Ratio and Particle Size Optimization for High‐Performance and High Tap Density P2/P3 Composite Cathode of Sodium‐Ion Batteries

Contact Info

Product

Resources

About

Design and Synthesis of Layered Na2Ti3O7 and Tunnel Na2Ti6O13 Hybrid Structures with Enhanced Electrochemical Behavior for Sodium‐Ion Batteries

Cited by 112 publications

References 44 publications

Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na2Ti3O7 Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage

Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na2Ti3O7 Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage

Dopant Segregation Boosting High‐Voltage Cyclability of Layered Cathode for Sodium Ion Batteries

Simultaneous Component Ratio and Particle Size Optimization for High‐Performance and High Tap Density P2/P3 Composite Cathode of Sodium‐Ion Batteries

Contact Info

Product

Resources

About

Design and Synthesis of Layered Na₂Ti₃O₇ and Tunnel Na₂Ti₆O₁₃ Hybrid Structures with Enhanced Electrochemical Behavior for Sodium‐Ion Batteries

Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na₂Ti₃O₇ Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage

Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na₂Ti₃O₇ Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage