Study on oxygen deficiency in spinel LiNi0.5Mn1.5O4 and its Fe and Cr-doped compounds

Liu, Guoqiang; Zhang, Jingyi; Zhang, Xiaohui; Du, Yonghua; Zhang, Kai; Li, Guocheng; Han, Yu; Li, Chuanwen; Li, Zaiyuan; Sun, Qiang; Lei, Wen

doi:10.1016/j.jallcom.2017.07.202

Cited by 40 publications

(16 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mn in all LNMOs is supposed to be +4 valence based on the sample designation. Therefore, the generation of Mn 3+ can be ascribed to the oxygen vacancies formed during the firing process. ,, In the case of 5-Fe-LNMO, most of the Fe (+3 valence) appears to form an Fe-rich surface. The reduction of Mn 4+ can further increase the Mn/Ni disorder and therefore improve the conductivity.…”

Section: Results and Discussionmentioning

confidence: 99%

Long-Term Cycling of a Mn-Rich High-Voltage Spinel Cathode by Stabilizing the Surface with a Small Dose of Iron

Zou

Cui

Nallan

et al. 2021

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

The high-voltage, cobalt-free spinel cathode LiNi0.5Mn1.5O4 (LNMO) is receiving extensive attention for lithium-ion batteries due to its low cost, high operating voltage and energy density, superior power density, and good thermal stability. However, its high operating voltage hampers its stability with commercial electrolytes and makes its practical viability challenging. We present here a Mn-rich LNMO cathode to encourage the disordering of Mn and Ni in the lattice and the incorporation of a small dose of Fe into Mn-rich LNMO (Fe-LNMO) to improve the cycling stability. The introduction of Fe further increases the cation disorder between Mn and Ni, thus enabling a better rate capability. Electron energy loss spectroscopy analysis indicates that Fe is concentrated on the surface, and X-ray photoelectron spectroscopy analysis shows that Fe-LNMO alleviates the aggressive reaction between the cathode surface and the electrolyte, thus stabilizing the interface and cycle life. Furthermore, a full cell assembled with a graphite anode with an areal capacity of 3 mA h cm–2 displays a capacity retention of 90% over 300 cycles. The present work demonstrates an effective way to promote cation disordering and lower the surface reactivity of LNMO with the electrolyte, thereby enhancing the conductivity, stabilizing the cathode–electrolyte interphase, and making LNMO promising for practical applications.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Long-Term Cycling of a Mn-Rich High-Voltage Spinel Cathode by Stabilizing the Surface with a Small Dose of Iron

Zou

Cui

Nallan

et al. 2021

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

show abstract

“…Due to poor uniformity of the raw material mixture, LiNi 0.5 Mn 1.5 O 4 synthesized by the conventional solid-state method may contain rock-salt impurities and deliver a low specific capacity. To enhance the electrochemical performance of LiNi 0.5 Mn 1.5 O 4 , one efficient strategy is to dope with transition metal ions such as Na [19], Mg [20], Er [21], Fe [22], Ga [23], Ru [24], Cr [25], and Al [26] in the framework, to improve conductivity. Jianbing G. et al studied the effects of Ru doping and the doping amount on the properties of LiNi 0.5 Mn 1.5 O 4 cathode material [27,28].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Ru4+ Doping on LiNi0.5Mn1.5O4 with Two Crystal Structures

Xue

et al. 2022

Materials

View full text Add to dashboard Cite

Doping of Ru has been used to enhance the performance of LiNi0.5Mn1.5O4 cathode materials. However, the effects of Ru doping on the two types of LiNi0.5Mn1.5O4 are rarely studied. In this study, Ru4+ with a stoichiometric ratio of 0.05 is introduced into LiNi0.5Mn1.5O4 with different space groups (Fd3¯m, P4332). The influence of Ru doping on the properties of LiNi0.5Mn1.5O4 (Fd3¯m, P4332) is comprehensively studied using multiple techniques such as XRD, Raman, and SEM methods. Electrochemical tests show that Ru4+-doped LiNi0.5Mn1.5O4 (P4332) delivers the optimal electrochemical performance. Its initial specific capacity reaches 132.8 mAh g−1, and 97.7% of this is retained after 300 cycles at a 1 C rate at room temperature. Even at a rate of 10 C, the capacity of Ru4+-LiNi0.5Mn1.5O4 (P4332) is still 100.7 mAh g−1. Raman spectroscopy shows that the Ni/Mn arrangement of Ru4+-LiNi0.5Mn1.5O4 (Fd3¯m) is not significantly affected by Ru4+ doping. However, LiNi0.5Mn1.5O4 (P4332) is transformed to semi-ordered LiNi0.5Mn1.5O4 after the incorporation of Ru4+. Ru4+ doping hinders the ordering process of Ni/Mn during the heat treatment process, to an extent.

show abstract

“…The electrochemical properties of the spinel are among others related to the degree of disorder, doping, impurities, morphology, oxygen vacancy, and Mn 3+ content. Since these are interrelated to the structural factors, the oxygen vacancy has been identified as a key contributing structural factor due to its correlation with the degree of disorder and Mn 3+ content …”

Section: Introductionmentioning

confidence: 99%

“…Since these are interrelated to the structural factors, the oxygen vacancy has been identified as a key contributing structural factor due to its correlation with the degree of disorder and Mn 3+ content. 11 It is common knowledge that oxygen-vacant, Mn 3+ -rich LMNO exhibits improved electronic conductivity 12,13 and Li + transport for enhanced discharge capacity; 13 thus, the presence of Mn 3+ in LMNO is a critical factor in the search for highenergy LMNO-based LIBs as energy is dependent on the discharge capacity and voltage. However, Mn 3+ has the drawback of a disproportionation reaction, which causes the dissolution of the Mn 2+ into the electrolyte.…”

Section: Introductionmentioning

confidence: 99%

Defect-Engineered β-MnO_2−δ Precursors Control the Structure–Property Relationships in High-Voltage Spinel LiMn_1.5Ni_0.5O_4−δ

et al. 2021

View full text Add to dashboard Cite

This study examines the role of defects in structure–property relationships in spinel LiMn1.5Ni0.5O4 (LMNO) cathode materials, especially in terms of Mn3+ content, degree of disorder, and impurity phase, without the use of the traditional high-temperature annealing (≥700 °C used for making disordered LMNO). Two different phases of LMNO (i.e., highly P4332-ordered and highly Fd3̅m-disordered) have been prepared from two different β-MnO2−δ precursors obtained from an argon-rich atmosphere (β-MnO2−δ (Ar)) and a hydrogen-rich atmosphere [β-MnO2−δ (H2)]. The LMNO samples and their corresponding β-MnO2−δ precursors are thoroughly characterized using different techniques including high-resolution transmission electron microscopy, field-emission scanning electron microscopy, Raman spectroscopy, powder neutron diffraction, X-ray photoelectron spectroscopy, synchrotron X-ray diffraction, X-ray absorption near-edge spectroscopy, and electrochemistry. LMNO from β-MnO2−δ (H2) exhibits higher defects (oxygen vacancy content) than the one from the β-MnO2−δ (Ar). For the first time, defective β-MnO2−δ has been adopted as precursors for LMNO cathode materials with controlled oxygen vacancy, disordered phase, Mn3+ content, and impurity contents without the need for conventional methods of doping with metal ions, high synthetic temperature, use of organic compounds, postannealing, microwave, or modification of the temperature-cooling profiles. The results show that the oxygen vacancy changes concurrently with the degree of disorder and Mn3+ content, and the best electrochemical performance is only obtained at 850 °C for LMNO-(Ar). The findings in this work present unique opportunities that allow the use of β-MnO2−δ as viable precursors for manipulating the structure–property relationships in LMNO spinel materials for potential development of high-performance high-voltage lithium-ion batteries.

show abstract

Study on oxygen deficiency in spinel LiNi0.5Mn1.5O4 and its Fe and Cr-doped compounds

Cited by 40 publications

References 18 publications

Long-Term Cycling of a Mn-Rich High-Voltage Spinel Cathode by Stabilizing the Surface with a Small Dose of Iron

Long-Term Cycling of a Mn-Rich High-Voltage Spinel Cathode by Stabilizing the Surface with a Small Dose of Iron

The Effects of Ru4+ Doping on LiNi0.5Mn1.5O4 with Two Crystal Structures

Defect-Engineered β-MnO_2−δ Precursors Control the Structure–Property Relationships in High-Voltage Spinel LiMn_1.5Ni_0.5O_4−δ

Contact Info

Product

Resources

About

Study on oxygen deficiency in spinel LiNi0.5Mn1.5O4 and its Fe and Cr-doped compounds

Cited by 40 publications

References 18 publications

Long-Term Cycling of a Mn-Rich High-Voltage Spinel Cathode by Stabilizing the Surface with a Small Dose of Iron

Long-Term Cycling of a Mn-Rich High-Voltage Spinel Cathode by Stabilizing the Surface with a Small Dose of Iron

The Effects of Ru4+ Doping on LiNi0.5Mn1.5O4 with Two Crystal Structures

Defect-Engineered β-MnO2−δ Precursors Control the Structure–Property Relationships in High-Voltage Spinel LiMn1.5Ni0.5O4−δ

Contact Info

Product

Resources

About

Defect-Engineered β-MnO_2−δ Precursors Control the Structure–Property Relationships in High-Voltage Spinel LiMn_1.5Ni_0.5O_4−δ