Small
·
2022
·Vol. 18
·期 38
·2203620
·
IF 15.153
Hongsheng Liang,Limin Zhang,Hongjing Wu
High density and skin effect restrict the research progress of metal predominated electromagnetic wave absorbing (EMA) materials. Although some works try to solve it, they do not focus on the metal itself and do not involve the optimization of the active site of the inherent defects of the metal. In this work, the modulation of morphology, composition, interface, defects, and conductivity is achieved by adjusting the ratio of copper salt to reducing agent chitosan. Uniquely, the appearance of twin boundaries (TBs) accelerates the ability of the homogeneous interfaces to transfer charges, resists the oxidation of metal Cu 0 , keeps the high electric conductivity of Cu 0 nanoparticles, and enhances the conduction loss, which provides a boost for electromagnetic wave dissipation. As a result, the metal Cu 0 predominated absorber (Cu-NC (N-doped carbon)−10,) exhibits an ultra-width effective absorption band of 8.28 GHz (9.72–18.00 GHz) at a thickness of 2.47 mm and the minimum reflection loss ( RL ) value of −63.8 dB with a thickness of 2.01 mm. In short, this work explores the EM regulation mechanism of TBs compared with grain boundaries (GBs), which provides a new insight for the rational design of metal predominated EMA materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Tong Ye,Yajie Wang,Xiang Yao,Hongbin Li,Taishi Xiao,Kun Ba,Yi Tang,Changlin Zheng,Xiaoyong Yang,Zhengzong Sun
The precise design and synthesis of active sites to improve catalyst’s performance has emerged as a promising tactic for electrochemistry. However, it is challenging to combine different types of active sites and manipulate them simultaneously at atomic resolution. Here, we present a strategy to synthesize Re atom-doped Cu twin boundaries (TBs), through pulsed electrodeposition and boundary segregation. The Re-doped Cu TBs demonstrate a highly efficient nitrogen reduction reaction (NRR) performance. Re-doped Cu TBs showed a turnover frequency of ∼5889 s–1, ∼800 times higher than the pure Cu TB active centers (∼7 s–1). In addition to the “acceptance–donation” activation of N2 molecules, theoretical calculations also reveal that the Re–Re dimer on TB can boost the NRR and impede the hydrogen evolution reaction synchronously, rendering Re-doped Cu TB catalysts with high NRR activity and selectivity.
研究领域:
材料科学
·
电化学
·
催化反应
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Zhedong Liu,Cuihua Zeng,Jingchao Zhang,Jiawei Luo,Zhaoxin Guo,Zekun Li,Rui Liu,Wei-Di Liu,Jia Ding,Yanan Chen,Wenbin Hu
Li-rich cathode materials are one of the most potential candidates for next-generation Li-ion batteries. However, they suffer from severe capacity degradation because of cracks and the continuous structural transformation during cycling. Defect engineering can effectively tune the electronic and crystal structure of nanomaterials and improve the electrochemical performance of cathode materials. Up to now, it is challenging to introduce dense defects into the materials synthesized by conventional tube furnace calcination due to the thermodynamic and kinetic equilibrium. In this work, a non-equilibrium high temperature shock (HTS) strategy with ultra-fast cooling, accompanied by the processes of rapid heating and cooling, is reported to introduce the twin boundaries (TBs) into the Li1.2Ni0.13Co0.13Mn0.54O2. The rock-salt phase along the TBs acts as a rigid framework that mitigates the inherent phase transformation of Li-rich layered-oxide materials during cycling. Benefiting from the unique structure, Li1.2Ni0.13Co0.13Mn0.54O2 prepared by HTS method exhibits a superior reversible capacity of 278 mAh g-1 at 0.1 C, a high initial Coulombic efficiency of 81%, and capacity retention of 89.4% after 100 cycles at 0.5 C. This work exerts profound implications on understanding defect engineering for modulating structure and electrochemical performance of materials.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Energy Materials
·
2023
·
IF 27.8
Zhaoxin Guo,Haoran Jiang,Xinyuan Sun,Xinbo Li,Zhedong Liu,Jingchao Zhang,Jiawei Luo,Jinfeng Zhang,Xian-Sen Tao,Jianxu Ding,Xiaopeng Han,Rui Liu,Yanan Chen,Wenbin Hu
Defect engineering is demonstrated to be an important factor in enhancing the electrochemical performance of lithium-ion batteries by improving structural stability and ion diffusion. However, conventional synthetic methods have long and complicated processes, making it challenging to effectively and easily introduce defects into electrode materials. In this work, a high-temperature shock technique (HTS) with an ultrafast heating and cooling process that can quickly introduce twin boundaries (TBs) into phase-pure spinel LiMn 2 O 4 in seconds is reported. Various ex situ techniques reveal the crystallization mechanism of LiMn 2 O 4 during ultrafast synthesis. LiMn 2 O 4 with TBs exhibits a higher rate performance than that obtained from the traditional method. Additionally, alien elements can be evenly incorporated into LiMn 2 O 4 in seconds, resulting in excellent cycling performance. For instance, 2% Ni-doped LiMn 2 O 4 shows an initial capacity of 121 mAh g −1 and retention of 86.5% after 500 cycles at 1 C.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Peng Xu,Weiwei Lu,Linghui Qiao,Qianqian Zhu,Haitao Liu,Kexing Song
The increasing demand for lithium-ion batteries (LIBs) with high energy densities and long cycle lifetimes places stringent requirements on the copper foil used as a negative current collector. Although copper foil meeting these requirements can potentially be fabricated by additives, this approach does not enable breakthrough performance improvements because of poor stability, insufficient synergistic effects, and other issues of the conventional additives in the plating solution. Herein, we designed two functionalized ionic liquids (1-aminopropyl-3-methylimidazolium chloride, IL-Cl and 1-aminopropyl-3-methylimidazolium bromide, IL-Br) and used them as composite additives to comprehensively regulate the properties of copper foil. Under optimal conditions (the ratio of IL-Cl to IL-Br in the composite additive is 2:1), the copper foil possesses ultrahigh mechanical properties (the tensile strength and elongation were 509.6 MPa and 12.35 %, respectively). Further structural and electrochemical assessments revealed that the developed additives modulated crystal structure growth by increasing the electrodeposited overpotential of Cu 2 + ions, and enhanced copper foil properties by inducing grain refinement and augmenting the density of Σ3 twin boundaries. The action mode of the additives on the copper foil surface (adsorption behavior) and their coordination interactions with Cu 2+ ions were examined using theoretical calculations. Thus, this work provides theoretical guidance for modulating the properties of the copper foils to satisfy the requirements of high-performance LIBs.
研究领域:
材料科学
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电化学
·
纳米技术
·
储能
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Xiaokang Chen,Le Su,Yi Tan,Jian Yuan,Yujin Mou,Wei-Qiao Deng,Hao Wu
Platinum (Pt) electrocatalysts face a trade-off between catalytic activity and durability in the hydrogen evolution reaction (HER). Designing Pt with a predominantly exposed (1 1 1) facet while improving its intrinsic activity remains a challenging endeavor. In this study, we synthesize high-entropy alloy (HEA) catalysts containing PtPdAuCuCo, featuring tunable (1 1 1)/(1 1 1) twin boundaries (TBs) achieved by entropy modulation. The incorporation of TBs creates favorable convex sites that facilitates overpotentially deposited hydrogen, leading to fast HER kinetics. Density functional theory (DFT) calculations indicate that the presence of TBs strengthens the H adsorption due to enhanced electron transfer from the metal to the adsorbate, an effect not observed in TB-free HEAs with even greater Pt contents. Moreover, the HEA with TBs shows an upshifted d band center and increased bonding state occupancy compared to its TB-free counterpart. Consequently, it exhibits exceptional HER performance, achieving outstanding stability for 15 days without degradation and ultralow overpotentials of 51 and 72 mV at 10 and 100 mA cm −2 , respectively, outperforming TB-free HEAs. The mass activity reaches 3.05 A mg −1 Pt at 100 mV, exceeding that for TB-free HEA by 23.5 folds. Our findings highlight the potential of TB-engineering to optimize the activity-durability trade-off in Pt electrocatalysts.
研究领域:
材料科学
·
电化学
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NANO LETTERS
·
2024
·
IF 9.6
Jiamiao Ni,Lin Cao,Boan Zhong,Quan Li,Chongxiao Guo,Jian Song,Yue Liu,Minghui Lu,Tongxiang Fan
Grain boundaries (GBs) and twin boundaries (TBs) in copper (Cu) are two major planar defects that influence electrical conductivity due to their complex electron transport characteristics, involving electron scattering and electron concentration. Understanding their local electronic states is crucial for the design of future conductor materials. In this study, we characterized electron behaviors at TBs and GBs within one Cu grain using atomic force microscopy. Our findings revealed that, compared with GBs, TBs exhibit better current transport capability (direct-current mode) and larger electromagnetic loss (high-frequency microwave mode). Both kelvin probe force microscopy and theoretical analysis suggested that TBs with smaller lattice disorder possess lower density of states at the Fermi level. The reduced density of states may result in decreased electron scattering and a lower electron concentration at TBs. The latter can be highlighted by the high-frequency skinning effect, manifested as larger electromagnetic loss and weaker high-frequency conductivity.
研究领域:
材料科学
·
凝聚态物理
·
电气工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）