共查询到20条相似文献，搜索用时 93 毫秒
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高镍层状氧化物具有成本低、能量密度高的优点,被认为是新一代锂离子电池的理想正极材料。然而,由于在使用中其结构的耐久性与安全性问题,在实际应用过程中仍然面临着严峻的挑战。深入了解电极材料容量衰减过程中的结构演变对发展高性能层状氧化物电极材料具有重要的指导意义。本文综述了近年来高镍层状氧化物正极失效机理的研究进展,包括从高镍层状氧化物的内部结构演变、表面成分变化和热失控条件下的性质等方面,进行了详细的梳理。之后,本文介绍了国内外最新的高镍层状氧化物的改性策略,并对高镍氧化物正极结构研究的发展方向进行了总结和展望。 相似文献
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利用周期性体系的Hartree-Fock方法计算了以LiC6／LiNiO2锂离子二次电池的平均电压，结果与实验值相差 15％。计算表明，NiO2中嵌入一个Li原子变成LiNiO2后，负电荷主要从Li转移到O上，转移到Ni上的负电荷仅约20％，讨论了其对Jahn-Tell效应的影响。以Li0.5NiO2作为嵌锂中间物的代表，研究了锂离子的可能迁移路径。通过对NiO2和LiNiO2的电子态密度的计算，研究了NiO2在嵌锂过程中的能带变化及其对电极的电化学性质的影响。 相似文献
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为了探究铝对高镍层状氧化物在结构、形貌及性能方面的影响,本文采用两种不同的方式掺铝以制备NCA正极材料 （LiNi0.8Co0.15Al0.05O2）：一是固相法即将共沉淀合成的NC前驱体（Ni0.84Co0.16(OH)2）在混锂烧结过程混入铝源（纳米Al2O3或Al(NO3)3）;二是共沉淀法即直接在合成前驱体过程中混入铝源（Al2(SO4)3或NaAlO2）即合成NCA前驱体（Ni0.8Co0.15Al0.05(OH)2.05）后再混锂烧结. 结果表明,掺铝能够降低阳离子混排程度、维持层状结构的稳定性,改善材料在充放电循环过程的放电电压及中值电压大幅下降的情况,提高其循环性能. 其中以NaAlO2为铝源合成NCA前驱体所制备的NCA材料性能最优：在3.0 ~ 4.3 V充放电区间,0.1C倍率下首圈放电比容量达198 mAh·g-1,首次库仑效率可达94.6%,1C倍率下循环200圈后容量保持率达70%. 相似文献
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Hyeongwoo Kim Jihye Jang Prof. Dongjin Byun Dr. Hyung-Seok Kim Prof. Wonchang Choi 《ChemSusChem》2019,12(24):5253-5264
Ni-rich layered oxides are promising cathode materials for developing high-energy lithium-ion batteries. To overcome the major challenge of surface degradation, a TiO2 surface coating based on polydopamine (PDA) modification was investigated in this study. The PDA precoating layer had abundant OH catechol groups, which attracted Ti(OEt)4 molecules in ethanol solvent and contributed towards obtaining a uniform TiO2 nanolayer after calcination. Owing to the uniform coating of the TiO2 nanolayer, TiO2-coated PDA-LiNi0.6Co0.2Mn0.2O2 (TiO2-PNCM) displayed an excellent electrochemical stability during cycling under high voltage (3.0–4.5 V vs. Li+/Li), during which the cathode material undergoes a highly oxidative charge process. In addition, TiO2-PNCM exhibited excellent cyclability at elevated temperature (60 °C) compared with the bare NCM. The surface degradation of the Ni-rich cathode material, which is accelerated under harsh cycling conditions, was effectively suppressed after the formation of an ultra-thin TiO2 coating layer. 相似文献
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Ruixin Zhang Yangyang Wang Xiang Song Prof. Guoran Li Dr. Sheng Liu Prof. Xueping Gao 《ChemElectroChem》2020,7(9):2042-2047
Nickel-rich layered oxides with high reversible capacity are considered as the next-generation cathode materials for lithium-ion batteries (LIBs). However, capacity degradation induced by side reactions and structural degradation on the surface has been the main obstacle for their applications. In this work, a stable layer of La4NiLiO8 is coated on Ni-rich material of Li[Ni0.88Co0.09Al0.03]O2 (NCA) by a facile method. The formation process of the La4NiLiO8 layer is analyzed from both thermodynamic and dynamics aspects. The results indicate that oxygen migration evolution near the NCA surface is effectively reduced, thus improving the structural stability of the lattice and alleviating the side reactions on the surface. The electrochemical and thermal stabilities of NCA material are remarkably improved by coating the La4NiLiO8 layer. This work provides a strategy for effective coating functional materials on Ni-rich cathode materials for LIBs. 相似文献
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Dr. Dong Luo Xiaokai Ding Dr. Jianming Fan Zuhao Zhang Dr. Peizhi Liu Dr. Xiaohua Yang Prof. Junjie Guo Prof. Shuhui Sun Prof. Zhan Lin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23261-23266
Low initial Coulombic efficiency (ICE) is an obstacle for practical application of Li-rich Mn-based layered oxides (LLOs), which is closely related with the irreversible oxygen evolution owing to the overoxidized reaction of surface labile oxygen. Here we report a NH4F-assisted surface multicomponent integration technology to accurately control the ICE, by which oxygen vacancies, spinel-layered coherent structure, and F-doping are skillfully integrated on the surface of treated LLOs microspheres. Though the regulation on the removed amount of labile oxygen by surface integrated structure, the ICE of LLOs cathodes can adjust from starting value to 100 %. X-ray absorption spectroscopy, refined X-ray diffraction, and scanning transmission electron microscopy show that the removed labile oxygen mainly comes from Li2MnO3-like structure. Even operating at a high cut-off voltage of 5 V, the capacity retention of integrated sample at 200 mA g−1 is still larger than 98 % after 100 cycles. 相似文献
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Yu Zhang;Mingxia Yan;Xin Guo;Xu Zhang;Jihong Liu;Jiyang Zhang;Jiapeng Zhu;Shengli An;Guixiao Jia; 《International journal of quantum chemistry》2024,124(13):e27440
The aggregation of Li2MnO3-like domains in Li-rich layered oxides (LLOs) causes severe capacity/voltage fading, which seriously impedes their commercial applications. Here, we design Co-free Li-rich LiFeNiMnO system with dispersed small-sized Li2MnO3–like domains (D-LFNMO) and aggregated Li2MnO3-like domains (A-LFNMO) to investigate effects of Li2MnO3-like domain sizes and Fe content on structures and oxidation process using density function theory (DFT) calculations. De-lithiation structures, structural stability and oxidization mechanism of lattice oxygen ions are explored. Structural stability is finished through calculating oxygen release energies and migration energy barriers of Mn4+ ions based on a climbing image nudged elastic band (CI–NEB) method. Research shows that LLOs with dispersed small-sized Li2MnO3-like domains and the moderate Fe content would possess highly reversible oxygen redox and excellent structural stability and would exhibit superior cycling stability of high capacity. The findings provide new perspectives and concepts for designing high-energy Li-rich cathodes. 相似文献
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通过调整不同配锂量、不同焙烧温度以及包覆改性对高镍无钴二元材料性能的影响因素进行了研究。对不同原样和其改性后的材料进行了X射线粉末衍射(XRD)分析和首次充放电性能和倍率性能、循环性能等电化学性能测试。其中过锂量(质量分数)为5%,焙烧温度为820℃的材料性能优异,其首次放电比容量为171.6 mAh·g^-1,1C和3C的放电比容量分别为147.8、129.8 mAh·g^-1。对材料进行锰化合物(质量分数1.0%)包覆处理后,材料的残碱量下降明显,加工性能优异,倍率性能得到明显改善,1C和3C的放电比容量分别提升为156.5、141.8 mAh·g^-1。2Ah软包电池常温循环830周容量保持率为80%,高温循环345周容量保持率为80%。 相似文献
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Li[Mn1/3-x/3 Ni1/3-x/3 Co1/3-x/3 Crx ]O2系列正极材料的合成及性能研究 总被引：1，自引：0，他引：1
采用改进的固相法一步反应成功制备了掺杂Cr的系列正极材料Li[Mn1/3-x/3Ni1/3-x/3Co1/3-x/3Crx]O2(x=0, 0.015, 0.025, 0.050, 0.100),用XRD, SEM和充放电测试等考察了它们的物理性质和电化学性能.结果表明,所合成的正极材料具有O2层状结构,规则的形貌和均匀的粒径尺寸分布,其嵌锂脱锂均为一步机理.加入适量的Cr可提高该系列正极材料的电化学性能和循环稳定性.x=0.015时的正极材料电化学性能最佳,室温下其首次放电比容量为138.60 mAh·g-1,并且循环性能最好. 相似文献
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Dr. Won Mo Seong Dr. Kwang-Hwan Cho Ji-Won Park Dr. Hyeokjun Park Donggun Eum Myeong Hwan Lee Dr. Il-seok Stephen Kim Prof. Dr. Jongwoo Lim Prof. Dr. Kisuk Kang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(42):18821-18828
The rampant generation of lithium hydroxide and carbonate impurities, commonly known as residual lithium, is a practical obstacle to the mass-scale synthesis and handling of high-nickel (>90 %) layered oxides and their use as high-energy-density cathodes for lithium-ion batteries. Herein, we suggest a simple in situ method to control the residual lithium chemistry of a high-nickel lithium layered oxide, Li(Ni0.91Co0.06Mn0.03)O2 (NCM9163), with minimal side effects. Based on thermodynamic considerations of the preferred reactions, we systematically designed a synthesis process that preemptively converts residual Li2O (the origin of LiOH and Li2CO3) into a more stable compound by injecting reactive SO2 gas. The preformed lithium sulfate thin film significantly suppresses the generation of LiOH and Li2CO3 during both synthesis and storage, thereby mitigating slurry gelation and gas evolution and improving the cycle stability. 相似文献
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Heng Zhang Chunmei Li Gebrekidan Gebresilassie Eshetu Stphane Laruelle Sylvie Grugeon Karim Zaghib Christian Julien Alain Mauger Dominique Guyomard Tefilo Rojo Nuria Gisbert‐Trejo Stefano Passerini Xuejie Huang Zhibin Zhou Patrik Johansson Maria Forsyth 《Angewandte Chemie (International ed. in English)》2020,59(2):534-538
Lithium‐ion batteries (LIBs) have become ubiquitous power sources for small electronic devices, electric vehicles, and stationary energy storage systems. Despite the success of LIBs which is acknowledged by their increasing commodity market, the historical evolution of the chemistry behind the LIB technologies is laden with obstacles and yet to be unambiguously documented. This Viewpoint outlines chronologically the most essential findings related to today's LIBs, including commercial electrode and electrolyte materials, but furthermore also depicts how the today popular and widely emerging solid‐state batteries were instrumental at very early stages in the development of LIBs. 相似文献
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Dong Won Kim Dr. Soo Min Hwang Prof. Ji Beom Yoo Prof. Young-Jun Kim 《ChemElectroChem》2020,7(12):2621-2628
Electrode engineering is considered an essential step toward fabricating advanced Li-ion batteries (LIBs). Conducting agents play a critical role in determining both the electron conduction and Li-ion transport in electrodes and thus in enhancing battery performance. Here, we report the effect of carbon nanotube (CNT) addition on the electrochemical properties of LiNi0.6Co0.2Mn0.2O2 (NCM622) cathodes. By varying the CNT content from 0 to 2 wt% in the total weight percentage (2 wt%) of conducting agents containing carbon black, the rate capability and cycling performance are examined. The limiting factors affecting the electrochemical performance are probed by using electrochemical impedance spectroscopy and pulse polarization measurements. The results show that as the CNT content increases, the electrical conductivity of the electrode decreases and the porosity increases. The addition of 1 wt% CNT gives rise to the best rate and cycling properties for the NCM622 electrodes. The pulse measurements reveal that the CNT addition mitigates the concentration polarization upon charging/discharging at high current rates owing to the evolved micrometer-scale pores in the electrodes, thereby leading to better rate capability. The post-mortem analysis on the electrodes discharged at a high current rate by time-of-flight secondary ion mass spectroscopy mapping show that the CNT addition allows facile Li-ion transport from the electrolyte side into the NCM lattice, even in the vicinity of the bottom region (current collector side), which strongly corroborates the pulse polarization results. These findings suggest that the use of CNTs as a conducting agent is effective in improving the electrochemical performance of Ni-rich cathodes. 相似文献