Improvement of electrochemical properties of LiNi0.5Mn1.5O4 spinel prepared by radiated polymer gel method

Xu, Hongwei; Xie, Song; Ding, Ning; Liu, B.L.; Shang, Yun; Chen, C.H.

doi:10.1016/j.electacta.2005.12.014

Cited by 72 publications

(24 citation statements)

References 16 publications

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“…The TG curve indicates that there is an evident weight loss (19.3 wt.%) between 151 and 253°C due to the evaporation of surface-absorbed water. Another obvious weight loss ( 34.71 wt.%) observed from 253 to 332°C can be attributed to the decomposition of the carbonate, which is supported by exothermic peak around 305 °C from DSC curve [19,20]. The weight lose above 350 °C is negligible, indicating that the oxides have been obtained.…”

Section: Resultsmentioning

confidence: 58%

Hollow spherical LiNi0.5Mn1.5O4 built from polyhedra with high-rate performance via carbon nanotube modification

Wang

Zhao

et al. 2016

Sci. China Mater.

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can afford a high energy density of 658 W h kg −1 , which is higher than the traditional LiCoO 2 (620 W h kg −1 ) and LiFePO 4 (591 W h kg −1 ) cathode materials [3]. However, some drawbacks such as the fast capacity fading at high voltage [4] and the appearance of rock-salt phase at high temperature [5] limit the commercialization of LNMO.It has been widely acknowledged that the electrochemical property of electrode materials is strongly related to the particle size, crystallinity and morphology [6]. To improve the performance, a wide variety of nanostructured electrodes, such as nanorods [7], porous structures [8], hollow microcubes and microspheres [9], and core-shell microspheres [10], have been designed and utilized in LIBs. Among these nanostructures, the porous and hollow structures can increase the contact area between the electrode and electrolyte, which is beneficial to reduce the transport path of lithium ions. Zhu et al. [11] reported the synthesis of LNMO microspheres with larger pores, which exhibited excellent performance. Luo et al. [12] synthesized LNMO hollow microspheres with excellent cycling stability and rate capability, which was attributed to the short electronic/ionic diffusion distance and accommodated volume change derived from the hollow structure. Li et al. [13] designed uniform LiNi 1/3 Mn 1/3 Co 1/3 O 2 hollow microspheres with improved performance by using porous Mn 1.5 Co 1.5 O 4 microspheres as the template. All these literatures demonstrate that the rational structural design can significantly improve the electrochemical performance.The cycling performance and high-rate capability are highly dependent on the conductivity of electrode materials [14]. Surface modification has been proved to be an efficient strategy to enhance electronic conductivity [15]. Among all modifying materials, carbon nanotube (CNT) is an ideal high electronic conducting material. It can efficiently improve the sluggish electron transportation and ABSTACT Lithium nickel manganese oxide spinel (LiNi0.5-Mn1.5O4, LNMO) has attracted much attention as the cathode material for rechargeable lithium-ion batteries due to its high energy density and low cost. However, the short cycle life and poor high-rate capability hinder its commercialization. In this study, we synthesized hollow spherical LNMO built from polyhedral particles. The LNMO hollow structure guarantees sufficient contact with electrolyte and rapid diffusion of lithium ions. To enhance the conductivity, we use carbon nanotubes (CNTs) to modify the surface of the cathode. After CNT modification, the LNMO hollow structure manifests outstanding cycling stability and high-rate capability. It delivers a discharge capacity of 127 mA h g −1 at 5 C, maintaining 104 mA h g −1 after 500 cycles. Even at a high rate of 20 C, a capacity of 121 mA h g −1 can be obtained. The excellent electrochemical performance is ascribed to the unique structure and the enhanced conductivity through CNT modification. It is demonstrated that the CNTmodified hollow spherical LNMO...

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Section: Resultsmentioning

confidence: 58%

Hollow spherical LiNi0.5Mn1.5O4 built from polyhedra with high-rate performance via carbon nanotube modification

Wang

Zhao

et al. 2016

Sci. China Mater.

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“…The fourth weight loss is found after 8008C, and can be attributed to the loss of oxygen from decomposition of LiNi 0.5 Mn 1.5 O 4 . [28,29] It is clear from the results that decomposition of the precursor is complete at 3508C, but we selected 5008C for the calcination of the precursor, which not only ensures the complete decomposition of the organic framework but results in better crystallinity of the sample without compromising on the structure disintegration.…”

Section: Resultsmentioning

confidence: 99%

“…It is desired that manganese should be in the þ4 oxidation state because Mn 3þ is unstable and cause dissolution of the manganese ions and destabilization of the structure. [25,29] The 4.1-V plateau is more pronounced in samples prepared by solid-state reactions. [30,31] Fig.…”

Section: Discharge Behaviourmentioning

confidence: 99%

“…[24][25][26][27][28] Lack of a simple synthesis method and high-potential-resistance electrolytes are the two major hurdles in the commercialization of nickel-doped lithium manganates. [29] Various efforts have been made to develop a simple and efficient method for the preparation of LiNi 0.5 Mn 1.5 O 4 . These include solid-state, solution-phase, solgel, spray pyrolysis, thin-film, molten-salt, and combustion methods.…”

Section: Introductionmentioning

confidence: 99%

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Low-temperature Synthesis of Nanocrystalline LiNi0.5Mn1.5O4 and its Application as Cathode Material in High-power Li-ion Batteries

et al. 2014

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Nickel-doped lithium manganate spinels are a potential material for future energy storage owing to high cell potential and low price. Phase-pure spinels are difficult to prepare by conventional solid-state synthesis methods owing to loss of oxygen from the crystal lattice at high temperature (,8008C). Loss of oxygen causes Jahn-Teller distortion and Mn 4þ is converted into Mn 3þ , which results in undesired double-plateau discharge and reduction in capacity and stability of the material. In this study, nanocrystalline phase-pure LiNi 0.5 Mn 1.5 O 4 was prepared by co-precipitation with cyclohexylamine followed by calcination at a low temperature of 5008C. X-ray diffraction studies confirmed that a highly crystalline face-centred cubic product is formed with F-d3m space group. Scanning electron microscopy and transmission electron microscope studies confirmed that the particles are in the nano range with a porous structure. The as-prepared LiNi 0.5 Mn 1.5 O 4 showed a high initial specific capacity (up to 130 mA h g À1 ) and retained up to 120 mA h g À1 up to 50 cycles. The material has high conductivity and remains stable up to a 20-C discharge rate.

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“…either the voltage or the capacity can be increased. LiNi 0.5 Mn 1.5 O 4 spinel exhibits a voltage of about 4.7 V [1][2][3][4], which is higher than other electrode materials like LiMn 2 O 4 (4 V [5]), LiCoO 2 (4 V [6]) and LiFePO 4 (3.4 V [7]). In the past decade, many methods have been used to synthesize this high voltage material, including solid-state reactions [8][9][10], sol-gel processes [11,12], and co-precipitation [13,14].…”

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confidence: 99%

Nonstoichiometric Li1±x Ni0.5Mn1.5O4 with different structures and electrochemical properties

et al. 2012

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Li 1±x Ni 0.5 Mn 1.5 O 4 (x=0.05, 0) spinel powders were synthesized using a solid-state reaction. Their structures were characterized by X-ray diffraction, scanning electron microscopy and Raman spectroscopy. Their electrochemical properties for use as active cathode materials in lithium-ion batteries were measured. The LiNi 0. [15]. The oxygen-deficient composition LiNi 0.5 Mn 1.5 O 4-x is stable at temperatures over 800°C, but, when annealed at 700°C, the symmetry changes to P4 3 32. The 3 Fd m phase has a lower impedance and hence higher capacity at high rates. In addition, the cycle performance of the P4 3 32 phase is worse than that of the 3 Fd m phase because it must form an intermediate 3 Fd m phase during Li extraction. In addition to the annealing process, the synthetic method can also influence the space group of the LiNi 0.5 Mn 1.5 O 4 products [16,17].

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Improvement of electrochemical properties of LiNi0.5Mn1.5O4 spinel prepared by radiated polymer gel method

Cited by 72 publications

References 16 publications

Hollow spherical LiNi0.5Mn1.5O4 built from polyhedra with high-rate performance via carbon nanotube modification

Hollow spherical LiNi0.5Mn1.5O4 built from polyhedra with high-rate performance via carbon nanotube modification

Low-temperature Synthesis of Nanocrystalline LiNi0.5Mn1.5O4 and its Application as Cathode Material in High-power Li-ion Batteries

Nonstoichiometric Li1±x Ni0.5Mn1.5O4 with different structures and electrochemical properties

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