scarce resources, uneven distribution, and arduous recycling of lithium. Sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) operating with similar mechanism to that of LIBs are considered as affordable alternatives, [2] as a result of the desirable performances as well as much abundant resources of sodium and potassium. [3] The performances of the alkali metal-ion batteries depend much on the cathode and anode materials. Various types of cathode materials based on the reversible insertion/ extraction of alkali metal ions including transition metal oxides, fluorides, phosphates, hexacyanoferrates, and sulfates have been developed, and plenty of them exhibit desirable energy density and cycling performances. [4] Progress on the research for anode materials is relatively slow, however, as compared with their cathode counterparts. [5] Based on the reaction mechanisms, the anodes generally fall into three categories: insertion based, conversion based, and alloying based. [6] The conversion-based materials exhibit high theoretical specific capacities derived from the conversion reactions during the uptake of alkali metal ions. [7] Due to the large volume variations during charge/discharge, however, the conversion-based anodes exhibit rapid capacity fading. The alloyingbased materials deliver high specific capacity by the alloying reaction, but the material pulverization derived from repeated volume changes results in poor reversibility. [8] Insertion-based materials include titanium-based oxides and carbonaceous materials. Although the small volume change, high rate capability, and good cycling stability of titanium-based oxides are desirable, their high working voltages and low specific capacities are detrimental to the power density of the full cells. [9] Carbonaceous materials, including graphite, carbon nanotubes (CNTs), graphene, soft carbon (SC), hard carbon (HC), etc., are promising anode candidates for alkali metal-ion batteries. [10] Graphite has been developed as a practical anode for commercial LIBs. They have steady discharge curves and low operation potential (≈0.1 V vs Li + /Li), and the formation of stable graphite intercalation compounds (GICs) LiC 6 delivers a moderate theoretical intercalation capacity of 372 mAh g −1 . [11] While the intercalation capacities of graphite anodes for SIBs and PIBs are not satisfactory, delivering 35 mAh g −1 for SIBs with NaC 64Hard carbon (HC) is recognized as a promising anode material with outstanding electrochemical performance for alkali metal-ion batteries including lithium-ion batteries (LIBs), as well as their analogs sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). Herein, a comprehensive review of the recent research is presented to interpret the challenges and opportunities for the applications of HC anodes. The ion storage mechanisms, materials design, and electrolyte optimizations for alkali metal-ion batteries are illustrated in-depth. HC is particularly promising as an anode material for SIBs. The solid-electrolyte interph...
The quaternary ammonium salt cationic surfactant with long-chain alkyl and epoxy groups is very important intermediate product to synthesis novel functional surfactants. In this paper, a kind of quaternary ammonium salt cationic surfactant with long-chain alkyl and epoxy groups was synthesized by traditional method with epichlorohydrin and N-octadecyldimethylamine as raw materials. During the synthesis, the best reaction conditions have been obtained, that the reaction temperature is 35 °C, the reaction time is 4 h and the best mol ratio of epichlorohydrin to timethylamine is 5:1. In addition, the synthesized intermediate with long-chain alkyl and epoxy groups plays a very important roles in the development of cationic surfactant.
Microencapsulated phase change material (MEPCM) was successfully prepared by using paraffin as the core material and PMMA as shell material. Both raw materials are innocuous, cheap and rich in resource. The influences of the key factors (i.e. emulsifier, stabilizer, concentration of the oil phase) on synthesis reaction were systematically evaluated. Conditions of synthesis reaction were also optimized. The relevant research results indicate that the prepared microcapsules are regular spheres with smooth and compact surface. The diameter of these spheres ranges from 1 to 2 mm. No obvious overcooling or overheating phenomena can be observed even when the content of paraffin of MEPCM reaches approximately 50 wt%. TGA analyses indicate that the heat resistance of the microcapsule increases by 10 °C compared to the pure paraffin. Accelerated thermal cycling tests also verify that the MEPCM displays good thermal reliability. The MEPCMs synthesized in the current study have potentials for thermal energy storage purposes such as PCM slurries, textiles and building materials.
In order to prepare a novel superabsorbent resin based on cellulose, straw pulp cellulose was used as raw material, through etherification preparation of carboxymethyl cellulose, K2S2O8-Na2SO3 oxidationredox system as an initiator, acrylic acid, acrylamide as grafting monomer, crosslinking agent N, N-methylenebisacrylamide were used to synthesize the high water absorbent resin. The effects of reaction conditions to superabsorbent resin were studied using water absorbencies as evaluation standard, the optimum preparation technology was decided.
In order to research the removal effect of potassium ferrate to COD in the different wasterwater, the papermaking wastewater and the tanning wastewater were used as research objects. This paper was focused on evaluating the effectiveness of potassium ferrate preoxidation on COD removal by coagulation in different wastewater of papermaking and tanning. Potassium ferrate is a strong oxidant in the entire pH range: its redox potentials are 2.20 and 0.72 V in acidic and basic media, respectively ferrate (VI) ions will be reduced to Fe (III) ions or ferric hydroxide during the oxidation process, potassium ferrate has also the ability to act as coagulant. The removal efficiency was 78.21% to the papermaking wastewater and 85.51% to the tanning wastewater, respectively, when the dosage concentration of potassium ferrate was 20 mg/L. Altogether, potassium ferrate is a perfect sewage treatment agent to papermaking wastewater and tanning wastewater.
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