Abstract Developing biomass-derived three-dimensional porous carbon materials (porous carbon foam, PCF) has become a common strategy to obtain lightweight and efficient electromagnetic microwave-absorbing materials. Without the introduction of a template and subsequent activation process, several ultra-lightweight honeycomb PCF samples were successfully prepared from dried ballonflower (DB) by simple calcination, and the calcination temperature plays a decisive role in regulating the pore size, composition and microwave absorption properties of PCF samples. Furthermore, it is worth noting that different cutting directions also affected the hole size of the PCF sample as well as the microwave absorption performances. Under the combined effects of multiple reflections and scattering of PCF porous structure, dipole polarization of abundant heterogeneous atoms and good conductive loss of carbon material, the vertical cutting sample PCF-900V exhibits optimal microwave absorption performances with the minimal reflection loss (RL min ) value of -46.95 dB at 1.46 mm thickness and the effective absorption bandwidth (EAB) value of 5.52 GHz at 1.72 mm matching thickness respectively, indicating its great potential application as a promising lightweight and efficient microwave absorbing material.

Reflection loss

Carbon fibers

Discrete dipole approximation

10.21203/rs.3.rs-2349339/v1

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Hydrogen‐Bond‐Mediated Surface Functionalization of Boron Nitride Micro‐Lamellae toward High Thermal Conductive Papers

Advanced Materials Interfaces (2023)

Shulei Yu PeiChi Liao Yilin Zhang Yifei Li Huifeng Tian

Abstract Wide‐bandgap, layered hexagonal boron nitride (h‐BN) possesses excellent electrical insulation and ultrahigh thermal conductivity simultaneously, offering a perfect candidate for the growing demands of heating dissipations in modern chip industries and power electronics. Hybrids of h‐BN with polymers fulfill the thermal management materials (TMMs) requirement of flexibility, while the composite poses severe challenges in the interfacial bonding and excess thermal resistance. To date, the practical bonding between h‐BN intrinsic surfaces and polymer matrices remains elusive. This work reports on the effective alignment of h‐BN micro‐lamellae by introducing nitrogen‐atoms‐containing polymers as inter‐lamellae bridging mediums. Based on theoretical calculations the hydrogen bonding between polymer chains and the BN surface is revealed by differential charge densities mapping. It is shown experimentally that the neuron‐like polymer bundles strongly bonding surfaces of two neighboring h‐BN platelets as direct, microscopic evidence of the structure models. An extra alignment of h‐BN induced by this strong interfacial interaction leads to a higher degree of h‐BN stacking order, boosting the thermal conduction by eight times. These results reveal one unprecedented method to non‐covalently functionalize the h‐BN surface and expand the TMMs family in the dimension of the filler size, paving the way for exploring the larger‐sized ceramic TMMs.

Surface Modification

10.1002/admi.202202196

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A novel green BaZn2(BO3)2:Eu2+ phosphor for n-UV pumped white light-emitting diodes

Journal of Luminescence (2017)

Jie Liu Jian Ma Zhan‐Chao Wu Jianqiang Sun Zhenjiang Li

Green-light

10.1016/j.jlumin.2017.06.009

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Synergy Strategy of Electrical Conductivity Enhancement and Vacancy Introduction for Improving the Performance of VS₄ Magnesium-Ion Battery Cathode

ACS Applied Materials & Interfaces (2021)

Shiqi Ding Xin Dai Yuxin Tian Guanying Song Zhenjiang Li

The development of cathode materials with a high electric conductivity and a low polarization effect is crucial for enhancing the electrochemical properties of magnesium-ion batteries (MIBs). Herein, Mo doping and nitrogen-doped tubular graphene (N-TG) introduction are carried out for decorating VS4 (Mo-VS4/N-TG) via the one-step hydrothermal method as a freestanding cathode for MIBs. The results of characterizations and density functional theory (DFT) reveal that rich sulfur vacancies are induced by Mo doping, and N-TG as a high conductive skeleton material serves to disperse the active material and forms a tight connection, all of which collectively improved the electrical conductivity of electrode and increased the adsorption energy of Mg2+ (-6.341 eV). Furthermore, the fast reaction kinetics is also confirmed by the galvanostatic intermittent titration technique (GITT) and the pesudocapacitance-like contribution analysis. Benefiting from the synergistic effect of electrical conductivity enhancement and rich vacancy introduction, Mo-VS4/N-TG delivers a steady Mg2+ storage specific capacity of about 140 mAh g-1 at 50 mA g-1, outstanding cycle stability (80.6% capacity retention ratio after 1200 cycles under 500 mA g-1), and excellent rate capability (specific capacity reaches 77.1 mAh g-1 when the current density reaches 500 mA g-1). In addition, the reversible reaction process, intercalation mechanism, and structural stability during the Mg2+ insertion/extraction process are confirmed by a series of ex situ characterizations. This research provides a sustainable and scalable strategy to spur the development of MIBs.

10.1021/acsami.1c17023

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Citations (23)