Effects of equimolar Mg (II) and Si (IV) co-doping on the electrochemical properties of spinel LiMn2−2xMgxSixO4 prepared by citric acid assisted sol–gel method

Zhao, Hongyuan; Li, Fang; Liu, Xingquan; Cheng, Cai; Zhang, Zheng; Wu, Yue; Xiong, Weiqiang; Chen, Bing

doi:10.1016/j.electacta.2014.11.095

Cited by 50 publications

(18 citation statements)

References 36 publications

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“…When the Er-doping content increased, the mean diameter of the LiMn 2−x Er x O 4 (x = 0.01, 0.03, 0.05) samples showed a decreasing tendency. In particular, the LiMn 1.97 Er 0.03 O 4 particles shown in Figure 3c presented the most uniform size distribution, which is conducive to the enhancement of cycling life [21,28,32]. These results indicate that the introduction of erbium ions can effectively optimize the size distribution, which contributes to the improvement of the cycling stability.…”

Section: Resultsmentioning

confidence: 94%

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Enhanced Cycling Stability through Erbium Doping of LiMn2O4 Cathode Material Synthesized by Sol-Gel Technique

et al. 2018

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In this work, LiMn2−xErxO4 (x ≤ 0.05) samples were obtained by sol-gel processing with erbium nitrate as the erbium source. XRD measurements showed that the Er-doping had no substantial impact on the crystalline structure of the sample. The optimal LiMn1.97Er0.03O4 sample exhibited an intrinsic spinel structure and a narrow particle size distribution. The introduction of Er3+ ions reduced the content of Mn3+ ions, which seemed to efficiently suppress the Jahn–Teller distortion. Moreover, the decreased lattice parameters suggested that a more stable spinel structure was obtained, because the Er3+ ions in a ErO6 octahedra have stronger bonding energy (615 kJ/mol) than that of the Mn3+ ions in a MnO6 octahedra (402 kJ/mol). The present results suggest that the excellent cycling life of the optimal LiMn1.97Er0.03O4 sample is because of the inhibition of the Jahn-Teller distortion and the improvement of the structural stability. When cycled at 0.5 C, the optimal LiMn1.97Er0.03O4 sample exhibited a high initial capacity of 130.2 mAh g−1 with an excellent retention of 95.2% after 100 cycles. More significantly, this sample showed 83.1 mAh g−1 at 10 C, while the undoped sample showed a much lower capacity. Additionally, when cycled at 55 °C, a satisfactory retention of 91.4% could be achieved at 0.5 C after 100 cycles with a first reversible capacity of 130.1 mAh g−1.

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Section: Resultsmentioning

confidence: 94%

“…Among the existing, numerous solutions, many researchers generally prefer surface modification and cation doping [17,25,26,27,28,29,30]. The surface modification can make a positive contribution to the improvement of the cycling life by sealing off the active material from the electrolyte corrosion to suppress the manganese dissolution.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Cycling Stability through Erbium Doping of LiMn2O4 Cathode Material Synthesized by Sol-Gel Technique

et al. 2018

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“…On the other hand, the diffraction peak for the lattice plane (220) (2θ ≈ 30.9°), which arises only from diffraction of tetrahedral sites (8a) and could not be observed in an LMO XRD pattern due to low scattering ability of lithium atoms, was not observed in diffraction patterns of LiMg x Mn 2−x O 4 (x = 0.00, 0.02, 0.05, 0.10) samples in Figure 6 , which suggests that Mg 2+ ions used in doping only occupy octahedral sites (16d) in substitution of manganese ions [ 18 , 24 ].…”

Section: Resultsmentioning

confidence: 99%

“…[ 23 ]. Among potential doping elements, a transition nonmetal like Mg attracted a lot of attention due to its good electronic conductivity and its ability to stabilize the LMO host crystal structure [ 18 , 22 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] in addition to having many advantages, such as abundance, nontoxicity, low cost, and being lighter than transition metal elements.…”

Section: Introductionmentioning

confidence: 99%

Kinetic and Thermodynamic Studies on Synthesis of Mg-Doped LiMn2O4 Nanoparticles

2020

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In this work, a first study on kinetics and thermodynamics of thermal decomposition for synthesis of doped LiMn2O4 nanoparticles is presented. The effect of Mg doping concentration on thermal decomposition of synthesis precursors, prepared by ultrasound-assisted Pechini-type sol–gel process, and its significance on nucleation and growth of Mg-doped LiMn2O4 nanoparticles was studied through a method based on separation of multistage processes in single-stage reactions by deconvolution and transition state theory. Four zones of thermal decomposition were identified: Dehydration, polymeric matrix decomposition, carbonate decomposition and spinel formation, and spinel decomposition. Kinetic and thermodynamic analysis focused on the second zone. First-order Avrami-Erofeev equation was selected as reaction model representing the polymer matrix thermal decomposition. Kinetic and thermodynamic parameters revealed that Mg doping causes an increase in thermal inertia on conversion rate, and CO2 desorption was the limiting step for formation of thermodynamically stable spinel phases. Based on thermogravimetry experiments and the effect of Mg on thermal decomposition, an optimal two-stage heat treatment was determined for preparation of LiMgxMn2-xO4 (x = 0.00, 0.02, 0.05, 0.10) nanocrystalline powders as promising cathode materials for lithium-ion batteries. Crystalline structure, morphology, and stoichiometry of synthesized powders were characterized by XRD, FE-SEM, and AAS, respectively.

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“…According to the reported literature [ 35 ], the intensity ratio of (311)/(400) peaks can be optimized by replacing the Mn ions with some other cation ions in the spinel structure of LiMn 2 O 4 . If this intensity ratio is in the range of 0.96–1.10, the obtained samples usually show excellent cycling stability.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Cycling Stability of LiCuxMn1.95−xSi0.05O4 Cathode Material Obtained by Solid-State Method

Zhao

Bai

et al. 2018

Materials

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The LiCuxMn1.95−xSi0.05O4 (x = 0, 0.02, 0.05, 0.08) samples have been obtained by a simple solid-state method. XRD and SEM characterization results indicate that the Cu-Si co-doped spinels retain the inherent structure of LiMn2O4 and possess uniform particle size distribution. Electrochemical tests show that the optimal Cu-doping amount produces an obvious improvement effect on the cycling stability of LiMn1.95Si0.05O4. When cycled at 0.5 C, the optimal LiCu0.05Mn1.90Si0.05O4 sample exhibits an initial capacity of 127.3 mAh g−1 with excellent retention of 95.7% after 200 cycles. Moreover, when the cycling rate climbs to 10 C, the LiCu0.05Mn1.90Si0.05O4 sample exhibits 82.3 mAh g−1 with satisfactory cycling performance. In particular, when cycled at 55 °C, this co-doped sample can show an outstanding retention of 94.0% after 100 cycles, whiles the LiMn1.95Si0.05O4 only exhibits low retention of 79.1%. Such impressive performance shows that the addition of copper ions in the Si-doped spinel effectively remedy the shortcomings of the single Si-doping strategy and the Cu-Si co-doped spinel can show excellent cycling stability.

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Effects of equimolar Mg (II) and Si (IV) co-doping on the electrochemical properties of spinel LiMn2−2xMgxSixO4 prepared by citric acid assisted sol–gel method

Cited by 50 publications

References 36 publications

Enhanced Cycling Stability through Erbium Doping of LiMn2O4 Cathode Material Synthesized by Sol-Gel Technique

Enhanced Cycling Stability through Erbium Doping of LiMn2O4 Cathode Material Synthesized by Sol-Gel Technique

Kinetic and Thermodynamic Studies on Synthesis of Mg-Doped LiMn2O4 Nanoparticles

Enhanced Cycling Stability of LiCuxMn1.95−xSi0.05O4 Cathode Material Obtained by Solid-State Method

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