Application Of Porous Materials In Gas Adsorption And Electrochemical Energy Storage

The greenhouse effect and energy shortage caused by the over-exploitation of fossil fuels limited the development of society.The capture and storage of CO₂ is the most effective way to solve the greenhouse effect in a short time,while the only way to solve energy exhaustion is to find renewable green energy to replace non-renewable fossil fuels.Porous materials are widely used in various fields,such as CO ₂ capture,energy storage and catalysis,due to its large specific surface area and abundant pores.Based on porous materials,this article has carried out a series of researches to so lve the problem of greenhouse effect and energy shortage.Solid-supported amine adsorbents are extensively studied for CO ₂ capture due to high CO₂selectivity,low energy consumption and high adsorption performance.A series of ordered silicas with either bimodal or trimodal meso-macro porosities through a single or double-templating route has been designed as supports for polyethylenimines to make solid amine CO₂ adsorbents.Experimental results show that bimodal silicas with textural mesopores and interconnected macropores are ideal supports at medium amine loading,illustrated by significantly high amine efficiencies,trimodal silicas with internal mesopores,textural mesopores,and interconnected macropores show outstanding performance at high amine loading,which is the one of the highest values among composites reported so far.In addition,other factors affecting the adsorption amount of CO₂ were studied systematically,including the type of amine and different test temperatures.Energy storage technology is one of the key to solve the energy shortage problem.At present,lithium ion battery has been difficult to arrive t he requirement of society,and Lithium-sulfur battery is considered as the next generation of the most potential secondary battery system due to its numbers advantages,such as low price,high energy density and environmental friendliness.Nevertheless,the commercialization of Lithium-sulfur batteries confront many serious problems,such as volume expansion and“shuttle effect”cased by soluble lithium polysulfides?Li PSs?.This paper focuses on the design of sulfur anode to solve the above problems.The specific contents are as follows:?1?A SiO₂/S/PPY electrode material was Rational synthesized.This material can capture Li PSs in both physical and chemical ways,and a conductive polymer?polypyrrole?prepared by in-situ polymerization to improve the conductivity of Si O ₂/S composite.As a result,the electrode exhibits excellent cyclic stability,remaining above700 m A h g^-1 after 300 cycles.?2?A multi-functional N-doped carbon/graphene?NC/G?sheet is designed as a sulfur host,which has achieve high conductivity,strong anchoring and catalysis with Li PSs synchronously.Experimental and theoretical studies have proved that high nitrogen content not only has a good chemisorption effect on Li PSs,but also promotes the reaction transformation kinetics of Li PSs through catalytic action,thus achieving the efficient in situ anchoring-conversion of Li PSs.As a result,the electrode show a hig h initial capacity of 1380 m A h g^-1 and excellent cyclic stability.At high current density of2 C,the low capacity attenuation of each cycle was 0.037%Within 500 cycles.Even if without Li NO₃ additive to the electrolyte,a high surface capacity(6.2 m A h cm^-2)also can be achieved,which Prove that the multifunctional NC/G sheet as sulfur host can overcome many shortcomings of Lithium-sulfur batteries and achieve excellent electrochemical performance.