High ion conductivity of anion-exchange membrane is essential for the operation of alkaline anion-exchange membrane fuel cell. In this work, we demonstrated an effective strategy to enhance the conductivity of anion-exchange membrane (AEM), by incorporation of quaternized cellulose nanocrystal (QCNC) for the first time. Morphology observation demonstrated a uniform distribution of QCNC within QPPO matrix, as well as a clear QCNC network, which led to significant enhancement in hydroxide conductivities of composite membranes, for example, 2 wt % QCNC/QPPO membrane possessed a conductivity of 160% (60 mS cm, @80 °C) of that of QPPO. Furthermore, H/O cell performance of membrane electrode assembly based on 2 wt % QCNC/QPPO AEM showed an excellent peak power density of 392 mV cm at 60 °C without back pressure, whereas that of neat QPPO AEM was only 270 mV cm.

finally to the poor performance of Li-S batteries. [1][2][3][4][5][6][7][8][9][10] The state-of-the-art separators used in Li-S batteries are commonly porous polypropylene (PP) films, but their pores are too large to restrict polysulfide shuttling (Figure 1a). Lots of efforts have been made to mitigate this shuttle effect by physical repulsion or chemical adsorption routes such as filling or covering the pores with polymers, [11][12][13][14] metal-organic frameworks (MOFs), [15] metal oxides, [16,17] graphene, [18][19][20] modified carbon nanotubes, [21,22] etc. (Figure 1b). Unfortunately, the filled or covered pores also restrict the transportation of Li + ions, increase the inner resistance, and finally deteriorate the performance of Li-S batteries.In this report, we propose a new strategy to selectively coordinate high-order polysulfides with "tertiary amine layer (TAL)" by which to simultaneously keep the pores of the separator still open to lithium ion's transportation. The construction of the polysulfide tongs is based on the classic "soft and hard acid-base (SHAB) theory." Different from the literature chemical interaction strategies, the anchoring groups to trap polysulfide are chemically grafted onto the PP separator, which is tough and stable. Also, the dissolved high-order Li 2 S x (x = 4, 6, and 8) can be more efficiently grasped when they try to diffuse across the narrowed but opening complex pores (Figure 1c). Li 2 S x species are relatively "soft" acids as the positive charges are mainly dispersed on the surface of the agglomerated polysulfide mole cules. Moreover, after the lithium ions are coordinated by sulfur, there are still "electron cloud holes" in Li 2 S x molecules to accept electrons from other molecules ( Figure S2, Supporting Information). In this regard, if we construct a "soft" base on the separator, the high-order Li 2 S x (x = 4, 6, and 8) soft acid can be grasped when they are further reduced and released in the cathode. On the contrary, lithium ion, which is commonly recognized as "hard" acid because of its small size and concentrated charge density, will be repulsed away by the "soft" base on the separator according to the SHAB theory. The chosen "soft" base for grasping polysulfide tong is tertiary amine (TA) group, which has a dispersed electron cloud and large head volume. TA group do not possess N-hydrogen atom, so we do not need to worry about the potential side reactions between active hydrogen and lithium-related compounds. Also, because the largest binding energy (E b ) between Li 2 S x Rechargeable lithium-sulfur batteries, which use sulfur as the cathode material, promise great potentials to be the next-generation high-energy system. However, higher-order lithium polysulfides, Li 2 S x (x = 4, 6, and 8), regardless of in charge or in discharge, always form first, dissolve subsequently in the electrolyte, and shuttle to the cathode and the anode, which is called "shuttle effect." The polysulfides shuttle effect leads to heavy loss of the active-sulfur materials. Literatu...

Carbonyl groups protect quaternary ammonium groups by reversible reaction with OH− ions. This protection is named the “rat-trap effect”.

Electrocatalytic hydrogenation is a promising method to synthesize high value-added chemicals under mild conditions. However, in the case of converting cinnamaldehyde (CAL) into cinnamyl alcohol (COL), this approach is accompanied by the competitive side reactions, including hydrodimerization, CC saturation, and hydrogen evolution. In this work, a high selectivity to cinnamyl alcohol of 88.86% at 58.00% conversion was successfully achieved on a thermally decomposed RuO2–SnO2–TiO2/Ti cathode with a rutile sosoloid crystal structure, which surpasses the low selectivity (<15%) over various metal electrodes. Density functional theory calculation findings demonstrate that CAL interacts with the active RuO2 sites preferentially via CO rather than CC, with the energy barrier of CAL hydrogenation toward COL being significantly reduced. The introduction of SnO2 is efficient to improve the Faradaic efficiency by restraining hydrogen evolution, but would result in dimers as the main products at high content. In addition, low pH value and high electrode overpotential benefit the generation of COL and the inhibition of dimerization products.

The Ti3C2@CF–S cathode features high sulfur loading capacity, strong polysulfide attachment, superior pulverization inhibiting properties, and demonstrates remarkable cycling stability.

Well‐organized hydroxide channels are constructed by introducing quaternary ammonium phthalocyanine (QAPc) into anion exchange membranes. A hydroxide conductivity as high as 236.2 mS cm−1@80 °C is successfully achieved by striking a balance between the self‐aggregation advantage and the weak basicity weakness of the QAPc side chains. The strong π–π interaction between QAPc macrocycles is utilized to force the positive charged head groups to aggregate for the formation of hydroxide channels, and trimethylamine (TMA) head groups are added to increase regional OH− mobility. 5 nm hydroxide channels are confirmed by synchrotron radiation and transmission electron microscope methods. Coarse‐grained molecular dynamics simulation provide further theoretical chemistry evidences for the enhanced OH− transportation mechanism in the QAPc‐containing AEMs.

The practical application of lithium-sulfur (Li-S) batteries is seriously hindered by severe lithium polysulfide (LiPS) shuttling and sluggish electrochemical conversions. Herein, the Co9S8/MoS2 heterojunction as a model cathode host material...

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