Direct CVD Graphene For Lithium-Sulfur Batteries

Chemical vapor deposition(CVD)technology is one of the most promising methods for controllable preparation of graphene.Nonetheless,graphene grown on traditional metal catalysts involves complex transfer and metal residue problems in subsequent applications,so it is particularly important to develop direct preparation of graphene on nonmetallic substrates.In addition,it is equally important to explore the practical applications of graphene as well as the preparation methods.This article mainly focuses on its application in lithium-sulfur(Li-S)batteries.Herein,we report a direct-CVD approach,mainly focus on sulfur host design and interlayer configuration with graphene.The electrochemical performances of Li-S battery will be improved by promoting the reaction kinetics.The main research content of this paper is summarized as follows:1.In this contribution,we report a green route to synthesize nitrogen-doped graphene(NG)nanosheets by salt-templated plasma-enhanced chemical vapor deposition(PECVD).The water-soluble nature of NaCl renders the facile removal of salt templates after synthesis and direct formation of NG nanosheets.Thus-fabricated NG accompanying excellent electrical conductivity and favorable solution processability possesses implications in printable energy storage devices.Accordingly,separator modification in Li-S batteries can be enabled via printing by employing our NG-based composite inks.This work thus represents a practical route for mass production of graphene inks with cost-effectiveness and eco-friendliness for emerging energy storage technology.2.Herein,defective graphene was in-situ synthesized on TiO2 nanotubes to achieve G-TiO2 heterostructure via a PECVD technique.Our practical experimentations and theoretical calculations reveal that G-TiO2 manifests bifunctional electrocatalytic functionalities:(i)enabling the storage of abundant interface charges due to the difference in the work function between graphene and TiO2,thereby enhancing the electrical conductivity of the interface and hence,promoting LiPS conversion;(?)synergizing the advantages of adsorptive TiO2 and conductive graphene,in turn framing a smooth adsorption-diffusion-conversion pathway for LiPSs.Our devised PECVD methodology paves a new route toward the facial and economic design of hetero-phased multi-functional hosts for high-performance Li-S batteries.3.We report an all-CVD approach to realize the direct growth of ReS2@NG heterostructure,which serves as an ultralight high-performance interlayer for elevated LiPS regulation via easy transfer onto the commercial separator.Benefiting from the two-dimensional vertically-erected nanostructure,adsorptive ReS2-conductive NG interface,and favorable electrical conductivity,thus-derived ReS2@NG interlayer readily enhances reaction kinetics for LiPS conversion and boosts the reutilization of trapped LiPS whilst guaranteeing smooth transportation of lithium ions.This work is anticipated to shed light upon the construction of CVD-enabled versatile 2D heterostructures for enriching the interlayer design with multifunctionality and cost-effectiveness.4.We use a copper-foam-assisted plasma-enhanced CVD approach to harness the direct formation of flexible graphene glass materials at various flexible glass substrates,and 5.5-inch-sized flexible graphene glass with improved macroscopic film uniformity is simply attained.The as-produced graphene glass possesses favorable flexibility,good conductivity,and can serve as transparent conductive layers for perovskite solar cells.Specifically,we used pyridine as the carbon source,realizing heteroatomic doping of graphene on the flexible substrate.Furthermore,the resulting flexible graphene glass materials readily serve as active electrodes for metal-free hydrogen evolution reaction.Our work further broadens the application prospect of direct chemical vapor deposition technology in the field of energy storage.