Faster Activation and Slower Capacity/Voltage Fading: A Bifunctional Urea Treatment on Lithium‐Rich Cathode Materials

Lin, Tongen; Schülli, Tobias U.; Hu, Yuxiang; Zhu, Xiulin; Gu, Qinfen; Luo, Bin; Cowie, Bruce C. C.; Wang, Luyao

doi:10.1002/adfm.201909192

Cited by 123 publications

(107 citation statements)

References 61 publications

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“…have reported that the O vacancies can be uniformly generated on the surface regions through a gas‐solid interface reaction without destroying the overall structure [27a,52] . Meanwhile, O vacancies can also be constructed on the surface of LRMC via the pyrolysis reaction of carbon materials, such as dopamine hydrochloride [54] and urea [27c,55] . The existence of O vacancies is evidenced by the increased peak intensity at 531.5 eV from the high‐resolution O1s XPS spectrum (Figure 2a).…”

Section: Defective Materials On High‐capacity Li‐based Batteriesmentioning

confidence: 97%

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

Qiao

Lin

Yan

et al. 2020

Chemistry An Asian Journal

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Current commercial Li-based batteries are approaching their energy density limitation, yet still cannot satisfy the energy density demand of the high-end devices. Hence, it is critical to developing advanced electrode materials with high specific capacity. However, these electrode materials are facing challenges of severe structural degradation and fast capacity fading. Among various strategies, constructing defects in electrode materials holds great promise in addressing these issues. Herein, we summarize a series of significant defect engineering in the high-capacity electrode materials for Li-based batteries. The detailed retrospective on defects specification, function mechanism, and corresponding application achievements on these electrodes are discussed from the view of point, line, planar, volume defects. Defect engineering can not only stabilize the structure and enhance electric/ionic conductivity, but also act as active sites to improve the ionic storage and bonding ability of electrode materials to Li metal. We hope this review can spark more perspectives on evaluating high-energydensity Li-based batteries.

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Section: Defective Materials On High‐capacity Li‐based Batteriesmentioning

confidence: 97%

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

Qiao

Lin

Yan

et al. 2020

Chemistry An Asian Journal

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“…formed by pyrolysis of urea could protect these cathodes from detrimental surface reactions with the electrolyte solution. [63] Interestingly, adjusting the content of Ni cations may also have a positive stabilization effect. [64] As reported by Shi et al, 0.5Li 2 MnO 3 •0.5LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathodes with high Ni content exhibit lower voltage fading than 0.5Li 2 MnO 3 •0.5LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathodes.…”

Section: Voltage Fadingmentioning

confidence: 99%

Surface Modification of Li‐Rich Mn‐Based Layered Oxide Cathodes: Challenges, Materials, Methods, and Characterization

Lei

et al. 2020

Advanced Energy Materials

116

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high energy and power density, long cycle life, low cost, and environmental benignity. [3] Due to the high capacity of the currently used graphite anode −372 mAh g-1 , [1b,4] commercial cathodes have become the bottleneck for improving the energy density. [5] In addition, cathode materials take up about 40% of the total material cost of typical LIB cells. It is therefore crucial to develop cathode materials with high energy density and low cost, while maintaining superior safety features. [6] Driven by the wide deployment of electric vehicles in recent years, the demand for safer cathode materials with higher capacity and lower cost has become imperative. [2b] The specific capacity depends on the inherent physical properties of the cathode materials. Commercial materials such as LiCoO 2 , Li(Ni x Mn y Co z)O 2 , Li(Ni x Co y Al z)O 2 , LiMn 2 O 4 and LiFePO 4 all possess discharge capacities below 200 mAh g-1. [7] Ni-rich NCM, NCA, and Li-rich oxides are all prospective cathodes for high-energy LIBs as they can exhibit high specific discharge capacities above 200 mAh g-1. [6c] As compared with Ni-rich NCM and NCA, Li-rich Mn-based layered oxide (LMLO) cathode materials are cheaper and have higher specific capacity. They can deliver an initial specific discharge capacity that approaches 300 mAh g-1 , nearly doubling the capacity of commercially used cathodes and close to the limit for lithiated transition metal oxides. [8] Figure 1 lists the main development milestones of LMLO. In 1997 a novel material, LiCoO 2-Li 2 MnO 3 , was found by Numata et al., [9] a discovery that initiated intensive work on high energy density cathode materials. This group studied these materials intensively and demonstrated their cycling stability in the range of 3.0-4.3 V versus Li. [10] In 1999, Kalyani et al. reported that Li 2 MnO 3 can undergo electrochemical activation at potentials >4.5 V versus Li. [11] Dahn et al. described the charge compensation mechanism of LMLO, [12] and these cathodes were shown to provide high capacity at high operational voltage (>4.5 V). [13] In 2004, Thackeray et al. explored xLi 2 M′O 3-(1-x)LiMn 0.5 Ni 0.5 O 2 cathode materials with M′ = Zn, Ti, or Mn, concluding that Li 2 M′O 3 and LiMn 0.5 Ni 0.5 O 2 in these composite materials were integrated by short-range interactions. [14] The following Rechargeable lithium-ion batteries have become the dominant power sources for portable electronic devices, and are regarded as the battery technology of choice for electric vehicles and as potential candidates for grid-scale storage. Commercial lithium-ion batteries, after three decades of cell engineering, are approaching their energy density limits. Toward continually improving the energy density and reducing cost, Li-rich Mn-based layered oxide (LMLO) cathodes are receiving more and more attention due to their high discharge capacity and low cost. However, commercialization has been hampered by severe capacity and voltage decay, sluggish rate capability, and poor safety performance during charge/discharge cyc...

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“…Professor Wang also used in situ SXPD to study structural changes of Li‐rich material. [ 129 ] They used a urea thermal treatment on Li 1.87 Mn 0.94 Ni 0.19 O 3 leading to oxygen deficiencies that excite Li 2 MnO 3 and improve Li migration. in situ SXPD was conducted to monitor the real time crystal structural transformation of primal and modified materials (LMR and LMR‐U), as shown in Figure 12A.…”

Section: Advanced Characterization Measurementmentioning

confidence: 99%

Section: Advanced Characterization Measurementmentioning

confidence: 99%

Interfacial Degradation and Optimization of Li‐rich Cathode Materials^†

Zhao

Lai

et al. 2021

Chin. J. Chem.

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High‐energy and safe lithium ion batteries (LIBs) are in increasing need as the rapid development of electronic devices, electric vehicles, as well as energy storage station. Li‐rich oxides have attracted a lot of attention due to their high capacity and low cost as cathode material for LIBs. However, they still suffer from the vulnerable cathode/ electrolyte interface, which presents the huge challenges of surface degradation and gas release, particularly at high state of charge. Some issues of Li‐rich cathode materials, such as moderate cycle stability and voltage decay, are in tight connection with electrode‐electrolyte interfacial side reactions. Research in the area of interfacial degradation mechanism and optimization strategies is of great significance as for Li‐rich cathode, and extensive efforts have been poured. This review aims to understand the degradation mechanism of Li‐rich cathode materials, and summarize the corresponding valuable and effective optimization strategies. Based on these considerations, we also have discussed the remaining challenges and the future research direction.

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Faster Activation and Slower Capacity/Voltage Fading: A Bifunctional Urea Treatment on Lithium‐Rich Cathode Materials

Cited by 123 publications

References 61 publications

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

Surface Modification of Li‐Rich Mn‐Based Layered Oxide Cathodes: Challenges, Materials, Methods, and Characterization

Interfacial Degradation and Optimization of Li‐rich Cathode Materials^†

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Faster Activation and Slower Capacity/Voltage Fading: A Bifunctional Urea Treatment on Lithium‐Rich Cathode Materials

Cited by 123 publications

References 61 publications

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

Surface Modification of Li‐Rich Mn‐Based Layered Oxide Cathodes: Challenges, Materials, Methods, and Characterization

Interfacial Degradation and Optimization of Li‐rich Cathode Materials†

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Interfacial Degradation and Optimization of Li‐rich Cathode Materials^†