Spray Drying Synthesis And Electrochemical Characterization Of S/C Composite Material

The rapid development of electric vehicles and grid-scale energy storage not only greatly extends the applied realms of the lithium-ion batteries but also puts forward urgent demands for the new rechargeable battery system with higher energy density and lower cost.Li-S redox couple possesses a super high theoretical energy density of 2600 Wh kg^-1,and sulfur also has the advantages of high natural abundance and low cost.Therefore,Li-S batteries have great potential to meet the emerging market demands.The Li-S battery suffers from the low conductivity of sulfur species,the large volume change during the cathode process,and the dissolution and migration of the long-chain intermediate polysulfides in the electrolyte,which always leads to the low sulfur utilization,low Coulombic efficiency and quick capacity fade.To solve these problems,various porous carbon materials are designed and used as matrix to host sulfur.By encapsulating the sulfur within the carbon pores,the conductivity of the sulfur cathode is greatly enhanced,and the dissoluble loss of the energy-bearing polysulfides is also depressed.Based on the S/C strategy,a sisnificant enhancement has been achieved for the electrochemical performance.But the fabrication of the S/C composites with elaborate architectures always involves complicated procedures,and most of them always have low productivity and cannot afford mass production.Such actuality seriously restricts the practical application of the Li-S batteries.To overcome the above problems,spray drying technology,which is a common technology in the manufacturing industry,has been successfully applied to synthesize S/C composite for high-performance S cathode.Here all the raw materials are easily obtained commercials.This spray drying route can be easily enlarged.The main work are as follows:?1?Ketjen black?KB?and graphene oxide?GO?are introduced to construct a hybrid host for S.The resulting KB-S@GO composite synthesized by spray drying demonstrates a quasi-core-shell structure:the KB-S hybrid composes the core and the GO sheets act as the shell.After a simple post heating process which facilitates the reduction of GO,the final KB-S@rGO composite reveals a high initial reversible capacity of 1250 mAh g^-1 at0.1C.After 100 cycles,it still remains reversible capacity of 883 mAh g^-1,showing excellent cycle stability.?2?A doughnuts mesoporous carbon?MPC?has been successfully prepared via Spray drying method with PAN as the carbon source and SiO₂ as the templates.The specific surface area and pore volume of the MPC-x can be controlled by regulating the SiO₂amount.The method is simple,low-cost and suitable for large-scale preparation.After compositing with elemental sulfur S,MPC/S-x dispalys good cycle stability and rate capability.