Qicheng Chen's research while affiliated with Jilin University and other places

In this work, a novel high entropy hydroxide NiCoMoMnZn‐layered double hydroxide(LDH) is synthesized as an electrode material for supercapacitors using a novel template re‐etching method to promote the energy density. As a positive electrode material for supercapacitors, NiCoMoMnZn‐LDH has the advantage of a uniform distribution of elements, high specific surface area, porous and stable structure. More importantly, the specific capacitance can reach 1810.2 F g ⁻¹ at the current density of 0.5 A g ⁻¹ , and the NiCoMoMnZn‐LDH//AC HSC assembled from the material has an energy density of up to 62.1 Wh kg ⁻¹ at a power density of 475 W kg ⁻¹ . Moreover, the influence of different compositions on their morphological, structural, and electrochemical properties is investigated based on the characterization results. Then, the synergistic mechanism among the components of the high entropy NiCoMoMnZn‐LDH is revealed in detail by DFT calculations. In addition, the synthesis strategy proposed in this work for high‐entropy hydroxides exhibits universality. Experimental results show that the proposed strategy successfully avoids not only phase separation and element aggregation in the formation of high entropy materials, but also reduces structural distortion, which is beneficial for efficient and large‐scale synthesis of high entropy hydroxides.

The study of gas–liquid two-phase flow and heat transfer in non-Newtonian fluids is of great significance for the research and development of refrigeration and energy storage. In this paper, the characteristics and influencing factors of the phase change reaction in microalgae slurry were studied by numerical simulation and experimental verification. In order to further study the rheological and heat transfer characteristics of gas–liquid two-phase flow in the collector, the effects of wall heat flux, inlet velocity and microalgae slurry concentration on the phase change reaction in microalgae slurry were studied. The results show that when the boundary conditions of microalgae slurry with the same concentration change, the phase transition of microalgae slurry is different. The higher the wall heat flux, the more forward the phase transition occurs, and the smaller the flow rate, the more forward the phase transition occurs. When the boundary conditions remain unchanged, the phase transition point of microalgae slurry with different concentrations is the same, and the concentration of microalgae slurry will not be affected. However, the deviation between the fluid temperature and the thermal conductivity of high-concentration fluid after phase change is larger than that of low-concentration fluids. The deviation in the fluid temperature reaches approximately 10 K, and the deviation in thermal conductivity reaches approximately 0.025 W/(m·K). Therefore, the change in the fluid temperature and heat transfer intensity after phase change in microalgae slurry is more intense than that of Newtonian fluids.

Plastic crystal neopentyl glycol (NPG) displays a colossal barocaloric effect akin to conventional refrigerants, rendering it as a highly promising solid‐state refrigerant. However, its practical application is restricted by its elevated phase transition temperature, inferior thermal conductivity, and weak mechanical response. Herein, a molecular design strategy is employed, wherein NPG molecules are substituted with trimethylolpropane (TMP) molecules, resulting in the successful synthesis of novel plastic crystals, designated as NPG0.75TMP0.25, with a phase change temperature of 283.7 K. To enhance the thermal conductivity, a dual encapsulation strategy is utilized to fabricate a highly oriented thermally conductive hybrid network composed of NPG0.75TMP0.25 and expanded graphite (EG) by using melt adsorption and pressure induction. The hybrid networks also significantly augment the mechanical properties of NPG0.75TMP0.25. The resulting composite barocaloric material exhibits a maximum entropy change of 223.8 J K⁻¹ kg⁻¹ achieved under pressure changes below 40 MPa and a thermal conductivity of 18.31 W m⁻¹ K⁻¹. Moreover, the composite exhibits high mechanical response and fatigue resistance. This study not only demonstrates the potential of composite barocaloric materials for practical applications but also significantly advances the engineering of barocaloric refrigeration.

Solar-driven hydrothermal pretreatment is an efficient approach for the pretreatment of microalgae biomass for biofuel production. In order to enhance the heat transfer, the magnetic fields effects on flow and heat transfer of nanofluids were investigated in a three-dimensional circular pipe. The magnetic fields were applied in different directions and magnetic field intensities to the flow. In this paper, Finite Volume Method was used to simulate flow and heat transfer of nanofluids under a magnetic field, and the Discrete Phase Model was selected to calculate two-phase flow, which was water mixed with metal nanoparticles. The research was also carried out with the various physical properties of nanoparticles, including the volume share of nanoparticles, particle diameter, and particle types. When the magnetic fields were applied along the X, Y, and Z directions and the intensity of magnetic fields was 0.5 T, the heat transfer coefficients of Cu-H2O nanofluids flow were increased evenly by 9.17%, 10.28%, and 10.32%, respectively. When the magnetic field was applied, the heat transfer coefficients and the Nusselt numbers were both increased with the increment of intensities of the magnetic field.