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Porous flow fields distribute fuel and oxygen for the electrochemical reactions of proton exchange membrane (PEM) fuel cells through their pore network instead of conventional flow channels. This type of flow fields has showed great promises in enhancing reactant supply, heat removal, and electrical conduction, reducing the concentration performance loss and improving operational stability for fuel cells. This review presents the research and development progress of porous flow fields with insights for next-generation PEM fuel cells of high power density (e.g., ∼9.0 kW L

The reactivity of garnet solid electrolytes toward humid air hinders their practical application despite their attractive, superior properties such as high Li+ conductivity and wide electrochemical window. Sealing garnets with organic solvents can not only prevent them from reacting with humid air but also render them compatible with other processing technologies. Therefore, the chemical and structural stability of garnets in organic solvents must be studied. In this study, we selected several commonly used organic solvents with different representative functional groups to investigate their stability with garnets and reaction mechanisms. The experiments and theoretical calculations revealed that all of the solvents reacted with garnets through Li-H exchange, and solvent acidity determined the reaction strength. Furthermore, the solvent acidity was closely correlated to the functional groups connected to H atoms, which can affect charge distribution. Solvents or the tautomer of the solvents with hydroxyl groups such as alcohol, acetone, and N-methyl pyrrolidone, which are relatively more acidic, can lead to a violent reaction with changes in the lattice parameters of garnets. Ether compounds and saturated aliphatic hydrocarbons with relatively low acidity are highly stable against garnets. The proposed reaction mechanisms and rules may help in selecting appropriate solvents for different applications of garnets.

Biomass-derived fuels are emerging alternatives to fossil fuels because of their renewability and better carbon balance. Fuel researchers from Zhejiang University have developed and improved a cata...

Targeted and nontargeted biopolymeric nanoparticles with identical hydrodynamic sizes and surface charges were quantitatively examined in terms of the pharmacokinetic and biodistribution differences in detail. In adding cancer cell targeting folate molecules to the surface of the heparin nanocarriers, the amount of drug delivered to the tumor is doubled, and tumor growth inhibition is significantly enhanced. The folate-targeted heparin particles offered similar therapeutic potentials compared to their synthetic long-circulating analogues, thus presenting a viable alternative for drug-delivery vehicle construction using biological polymers, which are easier for the body to eliminate.

In our efforts to obtain Pt-free oxygen reduction reaction (ORR) electrocatalysts with high efficiency for fuel cell and metal–air battery, design, and preparation of novel materials with desired morphology and active sites are vitally necessary. Herein, a novel MoC-based ORR catalyst with high efficiency is achieved. The proposed catalyst is comprised of ultrasmall-sized MoC nanoparticles (average size ∼ 1.5 nm) entrapped into 3D porous frameworks of N-rich graphene (NGr), which is synthesized by using layered C3N4 as a sacrificial template via a facile pyrolytic approach. Possessing unique structural features (including preferential O2 absorbing sites, good accessibility, favorable conductive and protective 3D frameworks of NGr), the MoC/NGr catalyst exhibits positive onset- and peak- potential at 0.93 and 0.80 V for ORR in alkaline media with good four-electron selectivity (n ≈ 4.0), which is promising and even competitive to commercial Pt/C, particularly in terms of cost-effectiveness, the ease of pre...