Synthesis and optimization of high-performance amine-based polymer for CO_(2) separation

Membrane technology features inspiring excellence from numerous separation technologies for CO_(2) capture from post-combustion gas.Polyvinylamine(PVAm)-based facilitated transport membranes show significantly high separation performance,which has been proven promising for industrial scale-up.However,commercialized PVAm with low molecular weight and excessive crystallinity is not available to prepare high-performance membranes.Herein,the synthesis process of PVAm was optimized by regulating polymerization and acidic hydrolytic conditions.The membranes based on PVAm with a molecular weight of 154 kDa and crystallinity of 11.37%display high CO_(2) permeance of 726 GPU and CO_(2)/N_(2) selectivity of 55 at a feed gas pressure of 0.50 MPa.Furthermore,we established a PVAm synthesis reactor with an annual PVAm solution(1%(mass))capacity of over 7000 kg and realized the scaled-up manufacture of both PVAm and composite membranes.

DEM simulations of tote blenders for enhanced axial mixing efficiency

The mixing performance of a multi-bladed tote blender is investigated using a graphics processing unit-based discrete element method program.The positioning,dimensions,and applicability of the baffles are systematically studied according to the axial mixing efficiency.The results indicate that the novel inclined multi-bladed baffles can break the symmetrical axial granular flow and introduce a more efficient convective flow into the granular mixing in the axial direction of the tote blender.Owing to the joint effects of convective mixing and asymmetrical granular flow,the axial mixing efficiency is increased by a factor of nearly 20.More importantly,the novel baffle placement approach exhibits excellent applicability to different operating conditions,particle shapes,and blender sizes.Additionally,the inclined baffles can prevent the segregation caused by shape discrepancies and improve the mixing homogeneity in the steady state.The novel baffle design is promising for applications in more complex industrial blenders for achieving a high axial mixing efficiency.

Advanced sodium-ion capacitor based on antimony-carbon composite anode

Alloy-type materials with the characteristics of high theoretical capacity,low sodiation/desodiation potential,and good conductivity are considered as one of the most promising anodes for sodium-ion batteries or capacitors.However,the large volume change during the sodiation leads to poor cyclability and slow kinetics,thus presenting the main issue impeding the practical application.Herein,we propose a facile wet chemistry and pyrolysis method to synthesize Sb-carbon composite that Sb nanoparticles or single atoms are confined and/or dispersed in the wrinkled carbon framework with high nitrogen content.This unique architecture of Sb-carbon composite increases atomic interface contact/interaction with Na~+,facilitating ion diffusion and alleviating the volume change of Sb during the charge/discharge process.Half-cell test shows that Sb-carbon composite exhibits a high-rate capability and stable cycling life.Furthermore,sodium-ion capacitors fabricated by employing Sb-carbon composite as anode and home-made active carbon as cathode,deliver both high-energy density of 157 Wh·kg^(-1)and high-power density of 25 kW·kg^(-1)as well as excellent cycling performance exceeding 4000 cycles.

Lanthanum-dopedα-Ni(OH)_(2)1D-2D-3D hierarchical nanostructures for robust bifunctional electro-oxidation

The development of advanced electrocatalysts for electro-oxidation reactions has attracted much attention because of the critical role of such electrocatalysts in improving the overall efficiency of coupled hydrogen production.We have developed an efficient lanthanum-dopedα-Ni(OH)_(2) bifunctional catalyst with a 1D-2D-3D hierarchical nanostructure.It shows superior activity and stability in the anodic oxygen evolution reaction(OER)and urea oxidation reaction(UOR).Enrichment of the edge sites and conducting La doping inα-Ni(OH)_(2) phase enable formation and stabilization of abundant local Ni^(3+)ions.This guarantees ultralow onset potentials in electro-oxidation reactions.The 1D-2D-3D hierarchical nanostructure significantly boosts the in situ generation of high-valence active species,which results in efficient and stable OER and UOR performances,and the synergistic merit of doping-induced facile reaction kinetics.Because of the structural benefits of a large surface area,charge-transfer promotion,good structural stability,and bifunctionality,a 1%La-dopedα-Ni(OH)_(2) hierarchical nanostructure gives superior OER and UOR performances with low overpotentials,large catalytic current densities,and excellent operational stability.It is therefore a promising catalyst for use in simultaneous alkaline wastewater treatment and hydrogen production.

Three-dimensional hierarchical Ca_(3)Co_(4)O_(9) hollow fiber network as high performance anode material for lithium-ion battery

Transition metal oxides have high specific capacity as anode materials for lithium-ion battery.But aggregation of particles and volume expansion during lithiation/delithiation restrict their application.In this work,a three-dimensional hierarchical Ca_(3)Co_(4)O_(9)hollow fiber network assembled by nanosheets is prepared by an electrospinning combined with heat treatment method to overcome these issues and to boost its lithium storage performance.As-synthesized sample possesses excellent cyclic stability(578.6 m A h g^(-1)at 200 m A g^(-1)after 500 cycles)and rate performance(293.5 m A h g^(-1)at 5000 m A g^(-1)),much better than those of commercial Co_(3)O4.Furthermore,the fast kinetics of the three-dimensional Ca_(3)Co_(4)O_(9)hollow fiber network is also confirmed by the variable scan rates CV tests and the EIS measurements,which is dedicated to the specific hierarchical hollow fiber network structure that provides shorter ion transport distances and higher electrical conductivity.This work supplies a universal approach to improve the electrochemical performance of transition metal oxides for lithium ion batteries.