RARE METALS
·
2023
·Vol. 43
·期 2
·658-670
·
IF 8.8
Peng Jia-Qi,Wei Yuan-Yuan,Liu Dong-Ming,Li Yun,Hu Bin,Huang Bin,Yang Jian-Wen,Xiao Shun-Hua,Wang Ren-Heng
Ultra-high nickel layered oxide cathode material with high energy density is the most promising material to improve the electrochemical performance of lithium-ion batteries (LIBs). However, the poor structural stability and severe surface/interface side reactions of the material lead to poor rate performance and cyclic stability, which limits its application in practice. In this paper, the dual-modification strategy of Co doping and La 2 O 3 coating is used to meet the above challenges. Co doping can effectively widen layer spacing and reduce Li + /Ni 2+ mixing, and La 2 O 3 coating can effectively eliminate the residual alkali on the surface of active material, inhibit the thickening of cathode electrolyte interphase (CEI) film and reduce surface/interface side reactions. Therefore, the modified material (NM90-CL) with excellent electrochemical properties is achieved through the synergistic enhancement of Co doping and La 2 O 3 coating. Its capacity retention rate can reach 77.9% after 200 cycles at 1.0 °C and 75.7% after 200 cycles at 5.0 °C. Its reversible capacity can up to 153.5 mAh·g –1 at 10.0 °C. This dual-modification strategy will provide theoretical guidance and technical support for the synthesis of other high-performance electrode materials. Graphical abstract
研究领域:
材料科学
·
电化学
·
电池技术
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DOI
高影响因子
ENERGY & FUELS
·
2023
·
IF 5.3
Ya-nan Zhou,Tiantong Zhang,Yong Zhai,Yifei Wang,Xingfei Tang,Ning Nie,Jinli Zhang,Wei Li
With the Keggin structure PMo12O403– of phosphomolybdic acid (PMA) taken into account, the interfacial physicochemical property of PMA was adjusted through Li-ion exchange, and then Li-exchanged PMA was adopted to modify the cathode material LiNi0.9Mn0.1O2 (NM91) via the solid-phase method, aiming at improving the rate performance and cycling stability of the cathode. The optimal ion-exchanged PMA (PMA-e2)-modified NM91 (named 91PMA-e2) shows an initial discharge capacity of 216.6 mAh g–1 at 0.1 C and a capacity retention of 84.8% after 100 cycles (1 C and 2.8–4.5 V) as well as the best rate performance, which is superior to those of pristine NM91. With characterization by X-ray diffraction (XRD), X-ray photoelectron spectroscopy, high-resolution transmission electron microscope, in situ XRD measurements, etc., it indicates that PMA-e2 modification can reduce the Li/Ni mixing degree but enlarge the thickness of the lithium layer (TLiO6) and facilitate Li+ diffusion. The results suggest that the Keggin structure of PMA as well as the acidity property and priority adsorption toward water molecules are associated with the Li-ion exchange degree. In combination with the depth-profiling XPS measurement of the spent samples experienced in 300 cycles, it illustrates that spent 91PMA-e2 possesses higher amounts of LiF and Ni3+ but a lower amount of LixPOyFz, which are due to the coating layer generated from the Keggin structure of PMA-e2. Such a Keggin structure has the capacity to trap trace amounts of water and inhibit the hydrolysis reaction of PF5, consequently maintaining the stable structure of the cathode and achieving superior cycling retention.
研究领域:
材料科学
·
电化学
·
储能技术
·
锂离子电池
·
表面改性
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Hang Feng,Yue Leng,Tiandong Chen,Yanxia Sun,Chunxi Hai,Yuan Zhou
Due to the scarcity and high cost of cobalt resources, the development of cobalt free batteries is considered to be the next stage of power battery research. Layered LiNi 0.9 Mn 0.1 O 2 has higher energy density and better magnification performance with good prospects. However, its fragile structural stability and surface interface problems result in inferior cycle performance and rate capability compared to cobalt-containing cathode materials with the same Ni content. In this study, low magnetic resistance Al 3+ is used as a doping element to enhance the structure of the material and inhibit Li/Ni disordering. As expected, The Ni-rich, Co-free cathode material doped with 2 mol% Al 3+ showed the best structure and interface stability, exhibiting a capacity of 166.1 mAh·g −1 at a rate of 1 C after 180 cycles in the voltage range of 2.7–4.3 V, which was higher than that of untreated LiNi 0.9 Mn 0.1 O 2 and other materials with Al 3+ doping. Al 3+ doping enhanced the material's rate and cycle performance. Cycling at an ultra-high rate of 5 C, the capacity retention rate reaches 86.4% after 100 cycles. The effectiveness of the modified method has been demonstrated in this study, providing a theoretical basis for the commercialization of the material to some extent.
研究领域:
材料科学
·
能源工程
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产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2024
·
IF 5.4
Seokyoung Choi,Wuliang Feng,Yongyao Xia
High nickel and Co-free layered cathodes (LiNi0.9Mn0.1O2, NM) for lithium-ion batteries (LIBs) have gained researchers’ interest recently because of their high energy density and being free of toxic elements, but they still suffer from inferior electrochemical performance due to the lattice instability during cycling. Herein, we successfully improved the electrochemical performance of NM using a high-entropy strategy. A high nickel Co-free multidoped high-entropy LiNi0.9Mn0.05Zr0.01Nb0.01Ti0.01Al0.01Mg0.01O2 (HE-NM, where HE represents high entropy with Zr, Nb, Ti, Al, and Mg dopants) cathode with five dopants was successfully synthesized. Owing to the effect of the multidopant, parasitic reactions and the accumulation of rock-salt phase were successfully suppressed, which led to uniformized interior stress and effectively inhibited microcracks during cycling. Consequently, HE-NM showed high thermal and structural stability with an initial discharge capacity of 206.35 mAh g–1 at 0.1 C and a retention of 76% after 100 cycles at 1 C, which showed a great advantage over the pristine NM (63%). This work provided a strategy for the stabilization of the NM cathode, which provided insight for the development of high-performance LIBs.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2026
·
IF 4.4
Xu Yuyang,Zhao Yugeng,Liao Jie,Sun Peng,Hu Shoulei,Huo Taotao,Zhang Jinli,Jiang Zhiyi,Li Wei
To enhance the electrochemical performance of high-nickel and cobalt-free cathode material LiNi 0.9 Mn 0.1 O 2 (NM), this study proposes a synergistic strategy integrating high-shear pH-regulated precipitation to fabricate uniform micron-sized structured precursors, with Se-surface modification to enhance the cycling stability. First, the optimal sample NM-8.1 was synthesized via high-shear precipitation with the controlling pH value of 8.1, exhibiting the initial discharge capacity of 208.3 mAh g −1 at 25 °C and 0.1 C (2.7–4.4 V) and the capacity retention of 79.9% after 200 cycles at 1 C. Then, Se-driven surface coating was prepared to improve the cycle stability for NM-8.1, and the optimized NM-1Se shows the initial discharge capacity of 210.7 mAh g −1 (25 °C, 0.1 C, 2.7–4.4 V), the capacity retention of 88.5% after 200 cycles (1 C) and 82.3% after 500 cycles at 5 C. After 200 cycles (1 C), the R ct value equals 60.42 Ω for NM-8.1, whereas 29.08 Ω for NM-1Se. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses indicate that both the uniform, micron-sized structured precursors and the Se modification can promote Li + diffusion, stabilize the lattice oxygen and decelerate the growth of charge transfer impedance, thereby enhancing the cycling stability of the cathode material. This work offers a generalizable paradigm for the synthesis of advanced electrode materials, providing valuable guidelines for optimizing the preparation of other high-energy-density batteries. Graphical abstract Synergistic pH-regulated precipitation and Se surface modification enhance the capacity, cycling stability, and reaction kinetics of cobalt-free Ni-rich cathodes for high performance lithium-ion batteries.
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DOI
高影响因子
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