ADVANCED MATERIALS
·
2020
·Vol. 32
·期 24
·2001740
·
IF 27.398
Weidong Zhang,Qiang Wu,Jinxin Huang,Lei Fan,Zeyu Shen,Yi He,Qi Feng,Guannan Zhu,Yingying Lu
The low Coulombic efficiency of the lithium metal anode is recognized as the real bottleneck to practical high-efficiency lithium metal batteries with limited Li excess. The grain size and microstructure of deposited lithium strongly influences the lithium plating/stripping efficiency. Here, a solubilizer-mediated carbonate electrolyte that can realize grain coarsening of lithium deposits (>20 µm in width) with oriented columnar morphology, which is in sharp contrast with conventional nanoscale dendrite-like lithium deposits in carbonate electrolytes, is reported. It exhibits improved Li Coulombic efficiency to 98.14% at a high capacity of 3 mAh cm −2 over 150 cycles, because the colossal lithium deposition with minimal tortuosity can maintain the bulk Li with continuous electron conducting pathway during the stripping process, thus enabling efficient Li utilization. Li/NMC811 full batteries, composed of thin Li anode (45 µm) and a high-capacity NMC811 cathode (16.7 mg cm −2 ), can achieve at least 12 times longer lifespan (200 cycles).
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED THERMAL ENGINEERING
·
2025
·
IF 6.9
Chengzhi Hu,Yong Cai,Huihui Wang,Xianfeng Hu,Xiangyuan Han,Yubai Li,Dawei Tang
The poor structural thermal stability of metal micro-nanostructured surfaces significantly reduces their durability and stability in enhancing boiling heat transfer, rendering them unsuitable for use in the engineering of phase change heat dissipation devices. In this study, nanograins with twin boundaries, which possess lower grain boundary energy and can effectively suppress the grain coarsening phenomenon, were successfully induced for the first time in nanowires to enhance boiling heat transfer. Long-term boiling tests, multiple start-stop boiling cycles, and multiple heat flux overload experiments demonstrated that the lower interface enthalpy of twin-structured nanowires effectively suppressed the issue of grain coarsening commonly found in polycrystalline nanowires. Polycrystalline nanowires experienced significant coarsening, leading to the formation of micro-hills, which raised the surface superheat by 5.8 K at a heat flux of 150 W/cm 2 . On the contrary, twin-structured nanowires showed minimal structural changes, resulting in only a 1 K fluctuation in surface superheat. The characteristics of increased surface wettability, enhanced liquid supply by capillary force, and increased active nucleation sites in twin-structured nanowires remain stable throughout rigorous boiling tests. This stability ensures that twin-structured nanowires exhibit excellent durability and stability in enhancing boiling heat transfer.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED ENGINEERING MATERIALS
·
2024
·Vol. 26
·期 23
·2401477
·
IF 3.4
Le Fu,Zihua Lei,Wenjun Yu,Yang Liu
Thermally driven grain coarsening is a commonly encountered issue in nanocrystalline ceramics, particularly in high-temperature environments. The intergranular glass film (IGF) constitutes a crucial component of most ceramics and plays a pivotal role in the process of grain coarsening. In this study, it is proposed to impede grain coarsening by constructing a chemically complex IGF comprising multiple dopants with distinct ionic radii. Ternary dopants encompassing Al 3+ , Y 3+ , and La 3+ ions are simultaneously incorporated into a ZrO 2 –SiO 2 nanocomposite. To fabricate the nanocomposite, an amorphous precursor powder with uniformly dispersed dopants is prepared using a chemical coprecipitation method, followed by rapid hot pressing to obtain a dense bulk sample. The distribution behavior of ternary dopants at IGFs between adjacent ZrO 2 nanocrystallites (NCs) is carefully examined. It is revealed that the ternary dopants coexist at the IGFs. Moreover, Si 4+ ions exhibit preferential enrichment at the IGFs. Remarkably, the presence of chemically complex IGFs significantly enhances the resistance to grain coarsening in ZrO 2 NCs up to 1000 °C. In these findings, valuable insights are offered for designing and fabricating nanocomposites with exceptional resistance against grain coarsening.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Metals
·
2025
·Vol. 15
·期 9
·930
·
IF 2.5
Jinhu Ju,Dan Huang,Haitao Xu,Duo Dong,Jiangpeng Lou,Yuan Xu,Jiao Shi,Liu Zhu
The fabrication of WC-based cemented carbides faced challenges including inhomogeneous composition and grain coarsening. To solve these problems, WC–Co cemented carbides were fabricated via spark plasma sintering (SPS) using core–shell WC–Co powders prepared by an electroless plating method. The effects of sintering pressure and Co content on the microstructure and mechanical properties of the cemented carbides were investigated. The results showed that, with increasing sintering pressure, the relative density of the sintered samples was improved (98.4–99.6%) while the grains were coarsened (0.94–1.07 μm). The optimal properties (fracture toughness 11.11 MPa·m1/2, and hardness 2100.3 HV30) were obtained when sintered with a pressure of 20 MPa. Grain coarsening at higher pressure (30 MPa) reduced the toughness of the cemented carbides. When the Co content was increased from 3 wt.% to 8 wt.%, fracture toughness was improved while the hardness of the cemented carbides was reduced, attributed to the intrinsic high toughness and low hardness of the Co phase. The WC–8 wt.% Co cemented carbides exhibited optimized synergic mechanical performance (hardness of 1874.2 HV30 and fracture toughness of 13.77 MPa·m1/2). This work elucidated the relationship between the key sintering parameters (pressure and Co content) and the microstructure and mechanical properties of the cemented carbides. The achievements obtained provide a theoretical foundation for high-quality fabrication of the WC–Co cemented carbides.
研究领域:
材料科学
·
陶瓷与复合材料
·
粉末冶金
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
ACTA MATERIALIA
·
2021
·
IF 8.203
Zhi Dong,Zongqing Ma,Yongchang Liu
Powder metallurgy generally is a preferred method to consolidate and prepare some refractory metals considering their high melting temperatures. However, sintering such materials to high density while maintaining fine grain structure is challenging, and generally require ultrahigh temperature or need to be assisted by external pressure. Especially, the preparation of nanostructured oxide dispersion strengthened (ODS) refractory metals at low temperature is more difficult because grain coarsening and densification are simultaneously hindered by the common oxide addition. Thus, it is of great sense to explore a kind of oxide that can be used as both strengthening phase and sintering accelerator. In this work, after extensive theoretical calculation and experimental observation, it is found that the accelerated sintering at low temperature can be achieved in W-HfO 2 system. In the absence of external pressure or activator, this system can be rapidly densified without undesirable grain coarsening at a relative low temperature of only 1480 ˚C. Through kinetic analysis and density functional theory (DFT) calculation, it was confirmed that the intergranular HfO 2 particles provide a rapid diffusion transport pathway for W atoms in support of densification at temperature of interest. As a result, this alloy exhibits a homogeneous microstructure with ∼97% relative density and ∼200 nm grain size , which renders our alloy with an ultrahigh compressive strength of ∼3 GPa, much higher than the reported values. We believe that the accelerated sintering mechanism found in our W-HfO 2 system can be applicable to other refractory metals to prepare high-density nanocrystalline alloys with excellent properties.
研究领域:
材料科学
·
冶金学
·
固体物理学
·
机械工程
✓ 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）