| As a new type of secondary battery energy storage system,lithium-sulfur battery（LSBs）has advantages such as high theoretical specific capacity(1675 m Ah g-1),high energy density(2600 Wh kg-1),low price,safety and green compared with previous energy storage devices,so it is considered to have broad application prospects.However,there are still some difficulties to be overcome before the practical application of LSBs,such as the poor electrical conductivity of sulfur as an active material,the volume expansion of sulfur in the charging and discharging process,and the shuttle effect caused by the migration and dissolution of polysulfide intermediates.Because of these problems,LSBs have the defects such as poor capacity,unstable cycle performance and fast capacity attenuation in practical application.It is an excellent method to solve the defects by combining sulfur as active.Because of its excellent and controllable aperture structure,large specific surface area,good electrical conductivity and catalytic performance,carbon aerogel materials can undertake the task of improving material properties with sulfur composite.In this paper,high specific surface carbon aerogel material and its derivative material nickel-doped carbon aerogel material have been prepared by a simple method as carbon based material and sulfur composite material,and the electrochemical properties of the material were further discussed.The main content of the paper is as follow:（1）In this paper,glucose and paraffin,which are common in daily life,are selected as raw materials,and hydrogel materials are prepared by reverse-phase emulsion polymerization under high speed shear at different speeds(7/8/9kr min-1).High specific surface carbon aerogel materials are prepared through freeze drying and high temperature activation steps,and the proportion of activator KOH is adjusted during activation operation.After that,BET specific surface area of the material was tested to analyze the structural changes of the material,and the preparation process of the material was explored.（2）On the basis of the above process,we doped nickel metal into carbon aerogel material by high temperature reduction method,nickel particles exist in pores of carbon aerogel materials,the addition of nickel metal can not only enhance the conductivity of the material,but also play the role of polar chemical adsorption on the"shuttle effect"as the carbon-based material in the lithium sulfur battery,enhance the electrochemical stability of the material together with the physical adsorption of carbon aerogel material.The composite cathode prepared by the composite of nickel-doped carbon aerogel material and nano sulfur can ensure the loading of sulfur,and at the same time can show a first discharge capacity of 757.55 m Ah g-1 at the current density of 0.5 C,and a discharge capacity of 602.18 m Ah g-1 after 200 cycles.The single-loop attenuation rate is only 0.12%.（3）In order to address the"shuttle effect"in lithium-sulfur batteries,we used surface electroless plating technology to coat the surface of carbon aerogel material with nano-nickel particles,which covered the surface of carbon aerogel material with uniformly distributed nickel particles.Compared with the previous high temperature reduction method,electroless plating method can doping nickel metal more evenly and efficiently.After that,the material and nano sulfur were compounded by liquid phase melting method.The composite cathode material showed an initial discharge capacity of 942.79m Ah g-1 in the charging and discharging process of lithium sulfur battery,and 455.24m Ah g-1 after 200 cycles. |
PDF Full Text Request