Water Boosts the Performances of Glass Anodes for Lithium-Ion Batteries

Owing to their disordered open network structure, oxide glasses are a promising class of anode materials for Lithium-Ion Batteries (LIBs). However, the relatively low capacities of glass anodes severely limit their practical application for large energy storage devices. Here we show an unconventional novel approach, which significantly enhances the electrochemical performances of glass anodes for LIBs. Specifically, we incorporated water into an electrochemically active glass system, i.e., TeO2-V2O5-P2O5 (TVP) glass powder via humidity treatment, and then mix the hydrated powder with additives to fabricate anode. The optimized humidity treatment led to the structural modification of the TVP glass powder, which boosted the capacity of the TVP anode by more than 200%, and maintained the reversible capacity for extra-long cycles. The boosted performances are associated both with the depolymerized structural network for Li+ diffusion and with the hydration-induced nanocrystals. These findings help develop superior glass electrodes in an economically effective way

Metal-Organic Framework Glass Anode with an Exceptional Cycling-Induced Capacity Enhancement for Lithium Ion Batteries

Metal organic frameworks (MOFs) hold great promise as high-energy anode materials for next-generation lithium ion batteries (LIBs) due to their tuneable pore structure and abundant reaction sites. However, since the pore structure of crystalline MOFs tends to collapse during lithium ion insertion and extraction, it has been a challenge to develop crystalline MOF-based anodes for high performance lithium ion batteries. Here we report a breakthrough in developing the high-performance MOF anodes. In detail, we have developed the first MOF glass anode, i.e., melt-quenched Cobalt-ZIF-62 glass anode with exceptional electrochemical performances. Compared with its crystalline counterpart, the Co-ZIF-62 glass anode exhibits significantly higher lithium storage capacity (306 mAh g-1 after 1000 cycles at the current density of 2 A g-1), outstanding cycling stability and superior rate performance. Amazingly, the Li-ion storage capacity of the MOF glass anode continuously rises with increasing the number of charge-discharge cycles and even tripled after 1000 cycles. We revealed the possible origin of the unusual cycling-enhanced performances of the MOF glass anode. These superior performances make MOF glasses ideal candidates for anode materials for LIBs. </p

Experimental and numerical study on the heat transfer performance of the radiant floor heating condenser with composite phase change material

Traditional hot-water ASHP systems have disadvantage of low energy efficiency due to the requirement of secondary heat exchange. To maintain the stability of indoor air temperature during defrosting, the existing ASHP systems adopt heat exchanger to store heat, which increases the system complexity. To overcome these obstacles, a novel ASHP system integrated with radiant floor heating condenser (RFHC) is proposed, which uses refrigerant as working fluid to exchange heat with indoor environment directly. In addition, the composite phase change material (CPCM) is added in the RFHC for heat storage. Experiments are conducted and results show that compared with traditional ASHP systems, the proposed system has higher energy efficiency and can reduce indoor air temperature fluctuation under defrosting condition. A detailed numerical model of the RFHC is established and validated with the experimental data, and then the impacts of the operating and structural parameters on the heat transfer performance of the RFHC system are investigated. Results show that under the indoor air temperature of test room keeps at 18.0 oC, the optimal operating condition of this system is the condensing temperature with 38.0 oC and the refrigerant mass flow rate with 3.8 kg· h-1. The optimal structural scheme of the RFHC is the copper pipe spacing with 0.25 m and the length of copper pipe with 12.0 m

Controllably produce renewable jet fuel with high-density and low-freezing points from lignocellulose-derived cyclopentanone

Production of jet fuel with high performance is attractive in the field of biomass utilization. This paper provides a way to controllably produce renewable jet fuel with high-density and low-freezing point by the condensation of biomass-derived cyclopentanone and followed hydrodeoxygenation. It is found that the freezing point of the jet fuel decreased rapidly with the increase of the content of spirocyclic alkane and the density increased gradually with content of tricyclic alkane. And the composition of jet fuel can be adjusted by controlling the reaction conditions of cyclopentanone condensation. At 30 degrees C and 3 h, the precursors of jet fuel were prepared by condensation of cyclopentanone over NaOH catalyst and the final obtained HDO products were comprised of 54.56% bicyclopentane, 31.88% tricyclic alkane and 13.56% spirocyclic alkane. The density of the jet fuel was 0.869 g.ml(-1 )and the freezing point was less than -60 degrees C. These parameters are obviously superior to that of commercial Jet-A

Achieving synergetic anion-cation redox chemistry in freestanding amorphous vanadium oxysulfide cathodes toward ultrafast and stable aqueous zinc-ion batteries

Flexible aqueous zinc-ion batteries (AZIBs) with high safety and low cost hold great promise for potential applications in wearable electronics, but the strong electrostatic interaction between Zn2+ and crystalline structures, and the traditional cathodes with single cationic redox center remain stumbling blocks to developing high-performance AZIBs. Herein, freestanding amorphous vanadium oxysulfide (AVSO) cathodes with abundant defects and auxiliary anionic redox centers are developed via in situ anodic oxidation strategy. The well-designed amorphous AVSO cathodes demonstrate numerous Zn2+ isotropic pathways and rapid reaction kinetics, performing a high reversible capacity of 538.7 mAhg-1 and high-rate capability (237.8 mAhg-1@40Ag-1). Experimental results and theoretical simulations reveal that vanadium cations serve as the main redox centers while sulfur anions in AVSO cathode as the supporting redox centers to compensate local electron-transfer ability of active sites. Significantly, the amorphous structure with sulfur chemistry can tolerate volumetric change upon Zn2+/H+ insertion and weaken electrostatic interaction between Zn2+ and host materials. Consequently, the AVSO composites display alleviated structural degradation and exceptional long-term cyclability (89.8% retention after 20 000 cycles at 40 Ag-1). This work can be generally extended to various freestanding amorphous cathode materials of multiple redox reactions, inspiring development of designing ultrafast and long-life wearable AZIBs.R.P. and F.C. contributed equally to this work. This work was supported by the National Key R&D Program of China (No. 2020YFB2007402), the Natural Science Foundation of Jiangsu Province (No. BK20220288), and the National Natural Science Foundation of China (No. 12174050 and 12234005), and the Fundamental Research Funds for the Central Universities