Influence of Nb5+ Doping on Structure and Electrochemical Properties of Spinel Li1.02Mn2O4

Li, Jianzhong; Yan-wen, Tian; Xu, Chen

doi:10.1016/s1005-0302(12)60136-4

Cited by 12 publications

(7 citation statements)

References 15 publications

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“…All diffraction peaks can be indexed as a cubic spinel structure and Fd 3̅ m space group, and all of the peaks are narrow and sharp, indicating good crystallinity. The patterns of Cr-0.1, Cr-0.2, and Nb-0.02 show no impurities composed of doped element, but the sample Nb-0.04 shows a slight LiNbO 3 peak at 2θ ≈ 24° . The pattern of undoped LNMO shows a weak peak related to Li z Ni 1– z O 2 at 2θ ≈ 43.7° .…”

Section: Results and Discussionmentioning

confidence: 93%

“…The patterns of Cr-0.1, Cr-0.2, and Nb-0.02 show no impurities composed of doped element, but the sample Nb-0.04 shows a slight LiNbO 3 peak at 2θ ≈ 24°. 18 The pattern of undoped LNMO shows a weak peak related to Li z Ni 1−z O 2 at 2θ ≈ 43.7°. 16 Nb doping weakens this peak, and the Cr-doped LNMO shows that no Li z Ni 1−z O 2 impurity for the strong bonding strength of chromium with oxygen is able to suppress Mn 3+ content in the LNMO.…”

Section: Resultsmentioning

confidence: 95%

“…Besides cycling performance, rate performance of LNMO is also improved by cation doping, especially by Cr doping. − It is found that Cr doping increases the electrical conductivity of LNMO . Nb doping was investigated in LNMO, LiMn 2 O 4 , and LiFePO 4 and also was found to improve the electrical conductivity of LiFePO 4 . Moreover, the rate performance of electrode materials is also dominated by particle morphology and the Li + diffusion coefficient according to J. Newman’s model .…”

Section: Introductionmentioning

confidence: 99%

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Effect of Chromium and Niobium Doping on the Morphology and Electrochemical Performance of High-Voltage Spinel LiNi_0.5Mn_1.5O₄ Cathode Material

Mao¹,

Dai

Xuan³

et al. 2016

ACS Appl. Mater. Interfaces

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Undoped, Cr-doped, and Nb-doped LiMn(1.5)Ni(0.5)O4 (LNMO) is synthesized via a PVP (polyvinylpyrrolidone)-combustion method by calcinating at 1000 °C for 6 h. SEM images show that the morphology of LNMO particles is affected by Cr and Nb doping. Cr doping results in sharper edges and corners and smaller particle size, and Nb doping leads to smoother edges and corners and more rounded and larger particles. The crystal and electron structure is investigated by XRD- and synchrotron-based soft X-ray absorption spectroscopy (sXAS). Cr doping and light Nb doping (LiNb(0.02)Ni(0.49)Mn(1.49)O4) improve the rate performance of LNMO. To explore the reason for rate-performance improvement, we conducted potential intermittent titration technique (PITT) and electrochemical impedance spectroscopy (EIS) tests. The Li(+) chemical diffusion coefficient at different state of charge (SOC) is calculated and suggests that both Cr and light Nb doping speeds up Li(+) diffusion in LNMO particles. The impedance spectra show that both R(SEI) and R(ct) are reduced by Cr and light Nb doping. The cycling performance is improved by Cr or Nb doping, and Cr doping increases both Coulombic efficiency and energy efficiency of LNMO at 1 C cycling. The LiCr(0.1)Ni(0.45)Mn(1.45)O4 remains at 94.1% capacity after 500 cycles at 1 C, and during the cycling, the Coulombic efficiency and energy efficiency remain at over 99.7% and 97.5%, respectively.

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Section: Results and Discussionmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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Effect of Chromium and Niobium Doping on the Morphology and Electrochemical Performance of High-Voltage Spinel LiNi_0.5Mn_1.5O₄ Cathode Material

Mao¹,

Dai

Xuan³

et al. 2016

ACS Appl. Mater. Interfaces

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“…Nb ions generally exhibit an oxidation state 5+ and have a similar ionic radius with Mn ions in the octahedral coordination environment. Their comparable sizes can facilitate ion substitution during calcination [36]. Such a substitution, which mostly takes place on the surface of the spinel, will not influence the oxidation state of Ni 2+ ions, but will contribute to reduction in the oxidation state of Mn ions from 4+ to 3+ and appearance of a Mn 3+ -rich region.…”

Section: Powder X-ray Diffraction (Xrd)mentioning

confidence: 99%

Enhancing the Stability of LiNi0.5Mn1.5O4 by Coating with LiNbO3 Solid-State Electrolyte: Novel Chemically Activated Coating Process versus Sol-Gel Method

et al. 2021

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LiNbO3-coated LiNi0.5Mn1.5O4 spinel was fabricated by two methods: using hydrogen-peroxide as activating agent and sol-gel method. The structure of the obtained cathode materials was investigated using a scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and the electrochemical properties of the prepared cathodes were probed by charge-discharge studies. The morphology of the coating material on the surface and the degree of coverage of the coated particles were investigated by SEM, which showed that the surface of LiNi0.5Mn1.5O4 particles is uniformly encapsulated by lithium innovate coating. The influence of the LiNbO3 coating layer on the spinel’s properties was explored, including its effect on the crystal structure and electrochemical performance. XRD studies of the obtained coated active materials revealed very small expansion or contraction of the unit cell. From the capacity retention tests a significant improvement of the electrochemical properties resulted when a novel chemically activated coating process was used. Poorer results, however, were obtained using the sol-gel method. The results also revealed that the coated materials by the new method exhibit enhanced reversibility and stability compared to the pristine and reference ones. It was shown that the morphology of the coating material and possible improvement of communication between the substrates play an important role.

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“…Among most, Nb is considered as a potential substitute element for Mn due to the stronger binding energy of Nb-O than Mn-O; which is beneficial for suppressing surface Mn dissolution during intercalation (Zhao et al, 2011;Dong et al, 2020). Li and coworkers (Li et al, 2012) reported that a small amount of niobium (Nb 5+ ) doping on the Li 1.02 Mn 2 O 4 can increase the conductivity and improve the cycling performance of the material. Several other studies on lithium manganese-based cathode materials showed that Nb-doping improves cycling performance, and cycling stability (Hu et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

The effect of niobium doping on lithium manganese oxide surfaces, LiMn2-xNbxO4: DFT study

Ramogayana

Maenetja

Ngoepe

2022

SATNT

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Lithium manganese oxide (LiMn2O4) is one of the promising cathode material for lithium-ion batteries (LIBs), however, it suffers from capacity fading mainly due to surface manganese (Mn2+) ion dissolution during Charge/discharge processes. Although many studies focused on reducing Mn-dissolution, surface modification has proven to be an ideal method of reducing Mn2+ ion dissolution in secondary Li-ion batteries. In this study, the density functional theory calculations were carried out to study the bulk properties and investigate the effect of Nb surface doping on major LiMn2O4 spinel surfaces. Upon surface Nb doping, we observed a decrease in surface free energy as compared to the surface energies of pure surfaces, indicating that the surface stabilizes upon doping. However, the (001) surface remained the most stable facet, with a similar trend of increasing energies and decreasing stability, i.e. (001) < (011) < (111). Due to the stronger binding energy of Nb-O as compared to Mn-O, doping with Nb can suppress the Mn dissolution during intercalation and hence improve the electrochemical performance.

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Influence of Nb5+ Doping on Structure and Electrochemical Properties of Spinel Li1.02Mn2O4

Cited by 12 publications

References 15 publications

Effect of Chromium and Niobium Doping on the Morphology and Electrochemical Performance of High-Voltage Spinel LiNi_0.5Mn_1.5O₄ Cathode Material

Effect of Chromium and Niobium Doping on the Morphology and Electrochemical Performance of High-Voltage Spinel LiNi_0.5Mn_1.5O₄ Cathode Material

Enhancing the Stability of LiNi0.5Mn1.5O4 by Coating with LiNbO3 Solid-State Electrolyte: Novel Chemically Activated Coating Process versus Sol-Gel Method

The effect of niobium doping on lithium manganese oxide surfaces, LiMn2-xNbxO4: DFT study

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Influence of Nb5+ Doping on Structure and Electrochemical Properties of Spinel Li1.02Mn2O4

Cited by 12 publications

References 15 publications

Effect of Chromium and Niobium Doping on the Morphology and Electrochemical Performance of High-Voltage Spinel LiNi0.5Mn1.5O4 Cathode Material

Effect of Chromium and Niobium Doping on the Morphology and Electrochemical Performance of High-Voltage Spinel LiNi0.5Mn1.5O4 Cathode Material

Enhancing the Stability of LiNi0.5Mn1.5O4 by Coating with LiNbO3 Solid-State Electrolyte: Novel Chemically Activated Coating Process versus Sol-Gel Method

The effect of niobium doping on lithium manganese oxide surfaces, LiMn2-xNbxO4: DFT study

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Effect of Chromium and Niobium Doping on the Morphology and Electrochemical Performance of High-Voltage Spinel LiNi_0.5Mn_1.5O₄ Cathode Material

Effect of Chromium and Niobium Doping on the Morphology and Electrochemical Performance of High-Voltage Spinel LiNi_0.5Mn_1.5O₄ Cathode Material