ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Yaoming Deng,Tianxing Kang,Zhen Ma,Xinxin Tan,Xiaona Song,Zheng Wang,Peipei Pang,Dong Shu,Xiaoxi Zuo,Junmin Nan
Under the abusive conditions, it is demonstrated that the thermal stability of LiCoO 2 and the safety of LiCoO 2 /graphite batteries are improved by doping and coating Al and Ti elements into the bulk structure and surface of LiCoO 2 . The trickle charge and the differential scanning calorimeter (DSC) results show that after coating Al and Ti oxides on the doped LiCoO 2 with 2000 ppm Al, the exothermic peak shifts to a higher temperature and the exotherm decreases, resulting in the increase of the thermal stability of LiCoO 2 . In addition, compared to the LiCoO 2 without Al doping, it is also indicated that the thermal stability of LiCoO 2 can be enhanced by doping Al, the exothermic peak of the LiCoO 2 with Al doping amount of 10000 ppm is up to 250 °C. Under the abusive testing conditions including thermal shock and overcharge, the safety evaluation results of pouch polymer LiCoO 2 /graphite batteries are in good agreement with the trickle charge and DSC results. These results reveal that the thermal stability of LiCoO 2 can be used as an indicator to evaluate the safety characteristics of LiCoO 2 /graphite batteries, and especially the introduction of Al and Ti into LiCoO 2 can effectively improve the safety of LiCoO 2 /graphite batteries under the abusive conditions.
研究领域:
材料科学
·
电池安全
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Liu Gao,Fujie Li,Guangrong Zeng,Xin Jin,Zhenyou Li,Chao Wang
Elevating the charging cut-off voltage is an effective strategy to increase the energy density of LiCoO 2 . However, unstable interfacial structures and unfavorable phase transitions in bulk are inevitably triggered during deep de-lithiation at high voltage. Herein, an integrated surface-to-bulk Ti-modification strategy is applied to LiCoO 2 , enabling uniform Li 2 TiO 3 coating on the surface and gradient Ti-doping toward the structural bulk. The resultant Ti-modified LiCoO 2 (T-LCO) electrode can be stably cycled up to 4.6 V, providing a high-rate capability of 137 mAh g −1 at 5C and a long-life stability with 80.5% capacity retention after 400 cycles at 1C, far outperforming the unmodified LiCoO 2 electrode with only 50.7% capacity retention. In situ X-ray diffraction characterization and density functional theory calculation reveal that the synergistic modification of T-LCO enhances Li + diffusion, facilitates the construction of high-quality cathode/electrolyte interphase, reduces the phase transition from O3 to H1-3 and Co3d/O2p band overlap, and restrains layer-to-spinel phase distortion, thus improving structural stability at 4.6 V. This work presents a “two birds one step” strategy to enhance the cycling stability and achievable capacity of high-voltage LiCoO 2 for developing high energy density lithium-ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Chao Sun,Bing Zhao,Ru-de Cui,Jing Mao,Ke-Hua Dai,He-Zhang Chen,Xia-hui Zhang,Jun-chao Zheng
Due to high volumetric energy density, the major market share of cathode materials for lithium-ion batteries is still dominated by LiCoO2 (LCO) at a 3C field. However, a number of challenges will be triggered if the charge voltage is increased from 4.2/4.3 to 4.6 V to further increase energy density, such as a violent interface reaction, Co dissolution, and release of lattice oxygen. Here, LCO is coated with the fast ionic conductor Li1.8Sc0.8Ti1.2(PO4)3 (LSTP) to form LCO@LSTP, while a stable interface of LCO is in situ constructed by the decomposition of LSTP at the LSTP/LCO interface. As decomposition products of LSTP, Ti and Sc elements can be doped into LCO and thus reconstruct the interface from a layered structure to a spinel structure, which improves the stability of the interface. Moreover, Li3PO4 from the decomposition of LSTP and remaining LSTP coating as a fast ionic conductor can improve Li+ transport when compared with bare LCO, and thus boost the specific capacity to 185.3 mAh g–1 at 1C. Benefited from the stable interface and fast ion conducting coating, the LCO@LSTP (1 wt %) cathode delivers a high capacity of 202.3 mAh g–1 at the first cycle (0.5C, 3.0–4.6 V), and shows a higher capacity retention of 89.0% than LCO (50.9%) after 100 cycles. Furthermore, the change of the Fermi level obtained by using a kelvin probe force microscope (KPFM) and the oxygen band structure calculated by using density functional theory further illustrate that LSTP supports the performance of LCO. We anticipate that this study can improve the conversion efficiency of energy-storage devices.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2024
·
IF 5.4
Haipeng You,Jiaqing Jiang,Long Chen,Chunzhong Li
In traditional electrolytes, due to the difference of donor number, the cyclic ethylene carbonate (EC) is usually used as the carrier of Li+, while the linear carbonate is used as the cosolvent. However, the poor desolvation ability of EC also leads to poor rate performance. Herein, we reversed the roles of carbonates, where the linear ethyl methyl carbonate (EMC) served as the Li+ carrier and the cyclic 3,3,3-trifluoropropylene carbonate (TFPC) acted as the cosolvent. This strategy helped significantly decrease the solvation effect while meeting the need for good solid electrolyte interphase (SEI) growth. Fluorobenzene (FB) was also introduced due to its low viscosity and high electrochemical stability. This electrolyte with a weakly solvated structure greatly improved the rate performance of electrodes. Moreover, the fluorine-rich interface introduced by the design effectively inhibited the dissolution of Co4+ in the high-voltage LiCoO2 (LCO) cathode. The LCO delivered a specific capacity of 177 mAh g–1 and a good cycle life with a high cutoff voltage of 4.6 V. A commercial high-voltage graphite||LCO pouch cell using this electrolyte showed a good capacity retention of 99.1% over 100 cycles and a high energy density of 285 Wh kg–1 at 0.3 C (counted by the mass of the whole battery) when charged to 4.5 V.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2020
·
IF 4.473
Chuan-Wei Wang,Yao Zhou,Jin-Hai You,Jian-De Chen,Zheng Zhang,Shao-Jian Zhang,Chen-Guang Shi,Wei-Dong Zhang,Ming-Hua Zou,Yang Yu,Jun-Tao Li,Lei-Ying Zeng,Ling Huang,Shi-Gang Sun
The LiCoO2 (LCO) cathode has been widely used in material markets, especially in conventional lithium ion batteries, due to its stable electrochemical performance. Increasing the working cutoff potential represents an efficient pathway to boost the capacity of LCO batteries; however, high working potentials usually induce severe Co3+ dissolution and extensive growth of solid electrolyte interphase (SEI) layer, leading to rapid degradation of the electrochemical performance. In this work, a high voltage cathode is prepared by the encapsulation of aluminum (Al)-doped LiCoO2 in a continuous Li4Ti5O12 (LTO) layer using a high-speed solid-phase coating method. The chemical composition evolution of the coating layer during the cycling process was characterized and evaluated through in situ XRD, XPS, and XAS analyses. The precipitation of aluminum fluoride (AlF3) at the defective sites of the LTO coating layer in the initial charge–discharge cycles effectively was found to fortify the structural integrity of the coating layer and prevent the etching of the LCO from undesirable side reactions with the liquid electrolyte. The modified LCO demonstrated an excellent capacity retention of 89.9% after 100 cycles at 0.2 C. The high-speed solid-phase coating method established in this study could be scaled up straightforwardly, providing a highly commercializable approach for large-scale production of stable high-voltage LCO cathode materials.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Teng Li,Ruizi Wang,Zikang Cai,Wenzhe Liu,Jiwei Song,Xixi Wu,Chunyan Cao,Liangjie Yuan
To date, LiCoO 2 has received extensive attention as a cathode material because of its unique characteristics. To satisfy the strong demand for high energy density , the cut-off voltage of LiCoO 2 is continuously increased. However, the structural instability of LiCoO 2 at a high cut-off voltage leads to capacity decay and many safety issues, which hinder further application of LiCoO 2 . Herein, YPO 4 is used to achieve a better electrochemical performance for LiCoO 2 at 4.55 V. In the synthesis process, YPO 4 is transformed into the Li 3 PO 4 and Y 2 O 3 phases, which are basically uniformly incorporated into the particle and form a composite with LiCoO 2 . Owing to the synergistic modification of Li 3 PO 4 and Y 2 O 3 phases, YPO 4 -modified LiCoO 2 materials show enhanced structural stability and excellent cycling performance. Particularly, 1.5% YPO 4 modified LiCoO 2 not only exhibits a reversible discharge capacity of 171.6 mAh g −1 over 500 cycles with 91.7% capacity retention, but also delivers a capacity of 144.5 mAh g −1 at 5 C (1 C = 274 mAh g −1 ). This work suggests that using rare-earth metal phosphates can be an effective strategy to improve the cycling performance of LiCoO 2 at 4.55 V.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Magnetic Resonance Letters
·
2023
·
IF 0
Suyu Gu,Guozhong Lu,Nianrui Guo,Juncheng Xu,Yu Jiang,Ming Shen,Bingwen Hu
LiCoO 2 is an important category of active cathode materials in lithium-ion batteries due to its high compacted electrode density, good thermal stability , and stable voltage platform. Recent works on LiCoO 2 have focused on the realization of higher charging voltages to fully utilize its high theoretical capacity. However, an unambiguous atomic-level local probe is essential for the understanding of structure-function correlation. Here we employ high-resolution solid-state nuclear magnetic resonance (NMR) spectroscopy to study the local atomic environments in LiCoO 2 synthesized with three common sintering methods. While one-dimensional 7 Li NMR shows distinct linewidth and subtle dependence on lithium over-stoichiometry, both 7 Li and 59 Co relaxation times are highly dependent on the sintering method. We prove that the two-step sintering method favors the elimination of unreacted Co 3 O 4 , thereby enabling the best discharge capacity in all-solid-state lithium batteries assembled with LiCoO 2 /LGPS/LiIn, which is in accordance with its narrowest 7 Li linewidth and the longest 7 Li/ 59 Co T 1 .
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
DOI
Journal of Energy Chemistry
·
2024
·
IF 14
Yueming Xia,Jianrui Feng,Jinhui Li,Yan Li,Zhengfeng Zhang,Xiaoqi Wang,Jianli Shao,Manling Sui,Pengfei Yan
Constructing robust surface and bulk structure is the prerequisite for realizing high performance high voltage LiCoO 2 (LCO). Herein, we manage to synthesize a surface Mg-doping and bulk Al-doping core-shell structured LCO, which demonstrates excellent cycling performance. Half-cell shows 94.2% capacity retention after 100 cycles at 3.0–4.6 V (vs. Li/Li + ) cycling, and no capacity decay after 300 cycles for full-cell test (3.0–4.55 V). Based on comprehensive microanalysis and theoretical calculations, the degradation mechanisms and doping effects are systematically revealed. For the undoped LCO, high voltage cycling induces severe interfacial and bulk degradations, where cracks, stripe defects, fatigue H2 phase, and spinel phase are identified in grain bulk. For the doped LCO, Mg-doped surface shell can suppress the interfacial degradations, which not only stabilizes the surface structure by forming a thin rock-salt layer but also significantly improves the electronic conductivity, thus enabling superior rate performance. Bulk Al-doping can suppress the lattice “breathing” effect and the detrimental H3 to H1-3 phase transition, which minimizes the internal strain and defects growth, maintaining the layered structure after prolonged cycling. Combining theoretical calculations, this work deepens our understanding of the doping effects of Mg and Al, which is valuable in guiding the future material design of high voltage LCO.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 106
·期 10
·6074-6084
·
IF 3.9
Yunjie Gou,Guangdong Li,Wang Sun,Jinshuo Qiao,Kening Sun,Zhenhua Wang
LiCoO 2 (LCO) has been widely adopted as the electrode for lithium-ion batteries (LIBs) which provide a solution for settling problems referring to energy and environment. The demand for rapid and controllable synthesis of LCO increases dramatically. In this work, reactive flash sintering (RFS), for the first time, was introduced to synthesize LCO rapidly and controllably based on simple oxide precursors. The as-prepared LCO, investigated by physicochemical property characterization, showed well-constructed and high crystallinity and controllable morphologies, in which the grain size varied with the magnitude of the applied limited current value, allowing for grain size modulation. Furthermore, the as-prepared LCO exhibited excellent performance in cyclic stability and rate capacity by contrast with that synthesized by the conventional solid-phase sintering method. This is admittedly attributed to better crystallinity and less lithium loss. Therefore, RFS provides a new approach for the manufacture of LCO electrode and has the potential to be applied to other electrode materials for LIBs.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
Energy Storage Materials
·
2021
·
IF 17.789
Pengfei Wang,Yan Meng,Yujue Wang,Lu Chen,Zhaokun Zhang,Wei Pu,Jianming Li,Chi Yang,Dan Xiao
LiCoO 2 with a cut-off voltage of 4.6 V (versus Li/Li + ) could increase by about 28% of energy density compared with the commercial 4.45 V LiCoO 2 cathode. However, severe issues such as oxygen evolution and dramatic phase transition strangle the practical application of 4.6 V LiCoO 2 . We herein develop a one-step wet chemical coating method at room temperature to stabilize the interface of LiCoO 2 under high voltage. Through the treatment of LiCoO 2 particles by LiAlH 4 solution, the oxygen framework of the surface was reconstructed forming a composite coating layer which is featured a morphology with an inside-out transition structure from order to disorder. Benifited from the Al-containing composite layer, an excellent cycling performance has been obtained on the treated commerical samples, delivering a capacity retention of 70.4% even after 1000 cycles. The key to the improvement of electrochemical performance is to restrain the loss of lattice oxygen which is further elucidated by the results from differential electrochemical mass spectroscopy (DEMS). The interface evolution in different depths was carefully investigated delineating the relationship between the fluorated interface and the enhanced performance. Since the introduction of aluminum hydroxide , it facilitates the capture of F − bringing the interface layer from oxide to more stable fluoride during the cycling. Combining with the first principles calculation results, the aluminum coating surface suppresses the evolution of surfacial oxygen confirmed by oxygen release energy, and the optimized models infer that the fluorinated layer can obviously stabilize the interface structure of LiCoO 2 . This study provides a direct coating method which confers a notable improvement on cycling stability of LiCoO 2 under high voltage and enables the implementation of high energy storage applications .
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2021
·Vol. 167
·期 16
·160557
·
IF 4.316
Guange Wang,Tong Wu,Borui Liu,Shanshan Gong,Qing Huang,Yuefeng Su,Feng Wu,Ryan M. Kelly
Considering that lithium-ion battery (LIB) is still an indispensable and important component of energy storage materials, the sustainable post-processing of spent LIBs in labs or enterprises becomes a tricky problem. Herein, a novel scheme is proposed to dissert the recycling of the spent LIBs. The LIB is recycled into Li(Ni0.9Co0.05Mn0.05)O2 (NCM90) cathode material with high specific capacity by introducing an innovative hydrometallurgy-coprecipitation treatment method. The spent LiCoO2 (LCO) cathode material is firstly leached by sulfuric acid, and the leachate is gradient used as the raw materials to resynthesize high-nickel NCM material by adjusting the leachate dosage to about 50%. Interestingly, when the dosage exceeds 50%, the crystal structure aggravates, and Li+/Ni2+ mixing improves. The specific capacity of regenerated battery is 181.4 mAh g−1 at 0.5 C (1 C = 200 mAh g−1) and the capacity retention achieves 93.2% after 100 cycles. The reasons can be attributed to the cation mixing and crystal strucure and the small amount of Al doping. In conclusion, this combined method recycling of LIBs has huge potential value for environment protection and production.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Chong Ni,Zhen Li,Kai Wang,Yongchao Liu,Yuanyun Dou,Wentao Wu,Hongyu Wang,Yu Yao,Hongfa Xiang,Xuyong Feng
Surface modification is a highly effective strategy to suppress side reactions between electrode materials and electrolytes. The preparation of coated electrode materials generally involves two steps: the synthesis of electrode materials and subsequent surface coating, which is a long and costly process. Here, we report a novel solid-state reaction method to prepare Li 2 ZrO 3 -coated LiCoO 2 in a single step. By controlling the cooling rate, the solid solubility of Zr in LiCoO 2 decreases, resulting in the precipitation of Zr 4+ on the surface and the formation of a Li 2 ZrO 3 coating layer. X-ray photoelectron spectroscopy, combined with a focused ion beam and high-resolution transmission electron microscopy, confirms the uniform Li 2 ZrO 3 coating on the surface of LiCoO 2 . Electrochemical performance testing shows that Li 2 ZrO 3 -coated LiCoO 2 exhibits enhanced cycle stability, even when charged to 4.5 V. After cycling at 1C for 200 cycles, Li 2 ZrO 3 -coated LiCoO 2 maintains a capacity of about 180 mAh g −1 , which is 94 % of the initial 193 mAh g −1 .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）