Lithium–sulfur batteries possess the merits of low cost and high theoretical energy density but suffer from the shuttle effect of lithium polysulfides and slow redox kinetics of sulfur. Herein, novel Co0.85Se nanoparticles embedded in nitrogen-doped carbon nanosheet arrays (Co0.85Se/NC) were constructed on carbon cloth as the self-supported host for a sulfur cathode using a facile fabrication strategy. The interconnected porous carbon-based structure of the Co0.85Se/NC could facilitate the rapid electron and ion transfer kinetics. The embedded Co0.85Se nanoparticles can effectively capture and catalyze lithium polysulfides, thus accelerating the redox kinetics and stabilizing sulfur cathodes. Therefore, the Co0.85Se/NC-S cathode could maintain a stable cycle performance for 400 cycles at 1C and deliver a high discharge specific capacity of 1361, 1001, and 810 mAh g–1 at current densities of 0.1, 1, and 3C, respectively. This work provides an efficient design strategy for high-performance lithium–sulfur batteries with high energy densities.

Lithium (Li) has garnered considerable attention as an alternative anodes of next‐generation high‐performance batteries owing to its prominent theoretical specific capacity. However, the commercialization of Li metal anodes (LMAs) is significantly compromised by non‐uniform Li deposition and inferior electrolyte–anode interfaces, particularly at high currents and capacities. Herein, a hierarchical three‐dimentional structure with CoSe2‐nanoparticle‐anchored nitrogen‐doped carbon nanoflake arrays is developed on a carbon fiber cloth (CoSe2–NC@CFC) to regulate the Li nucleation/plating process and stabilize the electrolyte–anode interface. Owing to the enhanced lithiophilicity endowed by CoSe2–NC, in situ‐formed Li2Se and Co nanoparticles during initial Li nucleation, and large void space, CoSe2–NC@CFC can induce homogeneous Li nucleation/plating, optimize the solid electrolyte interface, and mitigate volume change. Consequently, the CoSe2–NC@CFC can accommodate Li with a high areal capacity of up to 40 mAh cm–2. Moreover, the Li/CoSe2–NC@CFC anodes possess outstanding cycling stability and lifespan in symmetric cells, particularly under ultrahigh currents and capacities (1600 h at 10 mA cm−2/10 mAh cm−2 and 5 mA cm−2/20 mAh cm−2). The Li/CoSe2–NC@CFC//LiFePO4 full cell delivers impressive long‐term performance and favorable flexibility. The developed CoSe2–NC@CFC provides insights into the development of advanced Li hosts for flexible and stable LMAs.

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As miniaturized energy storage devices, flexible planar microsupercapacitors (MSCs) with high performance have broad applications on flexible electronics. However, traditional electrode fabrication methods (photolithography, laser writing, inkjet printing, etc.) are complex and expensive. In this work, a patterned interdigital electrode, which was prepared with a hard template of hydrophobic glue paper, was proposed. Peelable nickel nanocone arrays (NNAs) and polypyrrole nanotubes (PPyNTs) were electrochemically deposited on the substrate as 3D conductive frames and active material, respectively. The device demonstrates an areal capacitance up to 60.2 mF cm–2, high capacitance retention of 84.3% after 5000 cycles, as well as impressive mechanical performance that can work after 180° bending. Furthermore, a high energy density of 5.35 μWh cm–2 and power density of 2 mW cm–2 were obtained. Lastly, the fabricated MSCs presented great potential to integrate with series and parallel.

The free fatty acids (FFAs) of waste cooking oil (WCO) are readily esterified with crude glycerol in the presence of the solid superacid SO 4 2À /ZrO 2 -Al 2 O 3 . This reaction lowers the acidity of WCO before biodiesel production. The solid superacid SO 4 2À /ZrO 2 -Al 2 O 3 catalyzes both FFA esterification and TAG glycerolysis during the reaction. The conversion of FFA in the WCO with an acid value of 88.4 AE 0.5 mg KOH/g to acylglycerols was 98.4% under optimal conditions (mole ratio of glycerol to FFA ¼ 1.4:1; reaction time ¼ 4 h; reaction temperature ¼ 2008C; catalyst loading ¼ 0.3 wt%) obtained through an orthogonal experiment. The final FAME product with a FAME content of 96.9 AE 0.3 wt% yield was 94.8 wt%, after transesterification of the esterified WCO with methanol, catalyzed by potassium hydroxide. The FAME composition of the products produced by transesterification were identified and quantified by GC-MS. The results suggest that this new glycerol esterification process, using a solid superacid catalyst, affords a promising method to convert oils with high FFA levels, like WCO, to biodiesel. The process has the inherent advantage of easy separation steps for removing excess alcohol and significant savings in energy, when compared to acid catalyzed reactions with methanol to lower acidity.Practical applications: In this work, WCO with a high acid value was esterified with crude glycerol catalyzed by solid super acid, whose formula was expressed as SO 4 2À /ZrO 2 -Al 2 O 3 . There are distinct advantages to this new esterification process, which include easy separation of the excess crude glycerol by sedimentation or centrifugation, the use of the low cost reactant crude glycerol direct from the byproducts of transesterification, the potential to achieve a very low content of FFAs by post-refining to improve the yield of the final product, and time and energy saving are found as compared to the traditional methanol esterification process. This new technology provides a promising alternative method for processing feedstocks of high acid value, such as WCO, for the production of biodiesel.