In situ synchrotron radiation diffraction study of the Li+ de/intercalation behavior in spinel LiNi0.5Mn1.5O4-δ

Wang, Suning; Hua, Weibo; Zhou, Shuo; Liu, Laijun

doi:10.1016/j.cej.2020.125998

Cited by 30 publications

(21 citation statements)

References 32 publications

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“…Time-resolved in situ high-resolution synchrotron radiation diffraction (SRD) is a powerful approach to trace the structural evolution and phase transformation during inorganic reactions. [22][23][24] To study the formation mechanism of LNCM622O, in situ high-temperature SRD (HTSRD) was used to observe the changes of various phases from a mixture of the Li-free precursor, Ni 0.6 Co 0.2 Mn 0.2 (OH) 2 (NCM622OH) or Ni 0.6 Co 0.2 Mn 0.2 CO 3 (NCM622CO), together with lithium source to the final product under both isothermal and nonisothermal conditions. The experimental details are shown in the supplementary information.…”

Section: Resultsmentioning

confidence: 99%

Kinetic Control of Long‐Range Cationic Ordering in the Synthesis of Layered Ni‐Rich Oxides

Wang

Hua

Missyul

et al. 2021

Adv Funct Materials

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Deciphering the sophisticated interplay between thermodynamics and kinetics of high‐temperature lithiation reaction is fundamentally significant for designing and preparing cathode materials. Here, the formation pathway of Ni‐rich layered ordered LiNi0.6Co0.2Mn0.2O2 (O‐LNCM622O) is carefully characterized using in situ synchrotron radiation diffraction. A fast nonequilibrium phase transition from the reactants to a metastable disordered Li1−x(Ni0.6Co0.2Mn0.2)1+xO2 (D‐LNCM622O, 0 < x < 0.95) takes place while lithium/oxygen is incorporated during heating before the generation of the equilibrium phase (O‐LNCM622O). The time evolution of the lattice parameters for layered nonstoichiometric D‐LNCM622O is well‐fitted to a model of first‐order disorder‐to‐order transition. The long‐range cation disordering parameter, Li/TM (TM = Ni, Co, Mn) ion exchange, decreases exponentially and finally reaches a steady‐state as a function of heating time at selected temperatures. The dominant kinetic pathways revealed here will be instrumental in achieving high‐performance cathode materials. Importantly, the O‐LNCM622O tends to form the D‐LNCM622O with Li/O loss above 850 °C. In situ XRD results exhibit that the long‐range cationic (dis)ordering in the Ni‐rich cathodes could affect the structural evolution during cycling and thus their electrochemical properties. These insights may open a new avenue for the kinetic control of the synthesis of advanced electrode materials.

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Section: Resultsmentioning

confidence: 99%

Kinetic Control of Long‐Range Cationic Ordering in the Synthesis of Layered Ni‐Rich Oxides

Wang

Hua

Missyul

et al. 2021

Adv Funct Materials

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“…However, with increasing K + /F − co-doping content, the LNMO-KF0.01 and LNMO-KF0.02 yielded smaller peak areas of Mn 3+ than the pure LNMO, indicating that K + /F − co-doping reduced the Mn 3+ contents. A low Mn 3+ ion content may inhibit Jahn–Teller distortion and promote cycling performance [ 46 ]. To evaluate the Li + diffusion coefficient, CV tests for the five samples were conducted with a scan rate from 0.1 to 0.5 mV s −1 , as shown in Figure 7 b–f.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Electrochemical Performance of LiNi0.5Mn1.5O4 Composite Cathodes for Lithium-Ion Batteries by Selective Doping of K+/Cl− and K+/F−

Wei

et al. 2021

Nanomaterials

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K+/Cl− and K+/F− co-doped LiNi0.5Mn1.5O4 (LNMO) materials were successfully synthesized via a solid-state method. Structural characterization revealed that both K+/Cl− and K+/F− co-doping reduced the LixNi1−xO impurities and enlarged the lattice parameters compared to those of pure LNMO. Besides this, the K+/F− co-doping decreased the Mn3+ ion content, which could inhibit the Jahn–Teller distortion and was beneficial to the cycling performance. Furthermore, both the K+/Cl− and the K+/F− co-doping reduced the particle size and made the particles more uniform. The K+/Cl− co-doped particles possessed a similar octahedral structure to that of pure LNMO. In contrast, as the K+/F− co-doping amount increased, the crystal structure became a truncated octahedral shape. The Li+ diffusion coefficient calculated from the CV tests showed that both K+/Cl− and K+/F− co-doping facilitated Li+ diffusion in the LNMO. The impedance tests showed that the charge transfer resistances were reduced by the co-doping. These results indicated that both the K+/Cl− and the K+/F− co-doping stabilized the crystal structures, facilitated Li+ diffusion, modified the particle morphologies, and increased the electrochemical kinetics. Benefiting from the unique advantages of the co-doping, the K+/Cl− and K+/F− co-doped samples exhibited improved rate and cycling performances. The K+/Cl− co-doped Li0.97K0.03Ni0.5Mn1.5O3.97Cl0.03 (LNMO-KCl0.03) exhibited the best rate capability with discharge capacities of 116.1, 109.3, and 93.9 mAh g−1 at high C-rates of 5C, 7C, and 10C, respectively. Moreover, the K+/F− co-doped Li0.98K0.02Ni0.5Mn1.5O3.98F0.02 (LNMO-KF0.02) delivered excellent cycling stability, maintaining 85.8% of its initial discharge capacity after circulation for 500 cycles at 5C. Therefore, the K+/Cl− or K+/F− co-doping strategy proposed herein will play a significant role in the further construction of other high-voltage cathodes for high-energy LIBs.

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“…Synchrotron-based XRD provides a better way to understand the structural behavior of materials. [126][127][128][129][130] The optical layout of high- resolution powder diffraction (HRPD) beamline is shown in Fig. 4a.…”

Section: Structural Informationmentioning

confidence: 99%

Synchrotron radiation based X-ray techniques for analysis of cathodes in Li rechargeable batteries

et al. 2022

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In situ synchrotron radiation diffraction study of the Li+ de/intercalation behavior in spinel LiNi0.5Mn1.5O4-δ

Cited by 30 publications

References 32 publications

Kinetic Control of Long‐Range Cationic Ordering in the Synthesis of Layered Ni‐Rich Oxides

Kinetic Control of Long‐Range Cationic Ordering in the Synthesis of Layered Ni‐Rich Oxides

Enhanced Electrochemical Performance of LiNi0.5Mn1.5O4 Composite Cathodes for Lithium-Ion Batteries by Selective Doping of K+/Cl− and K+/F−

Synchrotron radiation based X-ray techniques for analysis of cathodes in Li rechargeable batteries

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