Sharma Vidushi, Mitlin David, Datta Dibakar
Department of Mechanical and Industrial Engineering, New Jersey Institute of Technology, Newark, New Jersey 07103, United States.
Materials Science and Engineering Program & Texas Materials Institute, The University of Texas at Austin, Austin, Texas, 78712-1591, United States.
Langmuir. 2021 Feb 16;37(6):2029-2039. doi: 10.1021/acs.langmuir.0c02893. Epub 2021 Feb 1.
We present comprehensive first-principles density functional theory (DFT) analyses of the interfacial strength and bonding mechanisms between crystalline and amorphous selenium (Se) with graphene (Gr), a promising duo for energy storage applications. Comparative interface analyses are presented on amorphous silicon (Si) with graphene and crystalline Se with a conventional aluminum (Al) current collector. The interface strengths of monoclinic Se (0.43 J m) and amorphous Si with graphene (0.41 J m) are similar in magnitude. While both materials (-Se, -Si) are bonded loosely by van der Waals (vdW) forces over graphene, interfacial electron exchange is higher for -Si/graphene. This is further elaborated by comparing the potential energy step and charge transfer (Δ) across the graphene interfaces. The interface strength of -Se on a 3D Al current collector is higher (0.99 J m), suggesting a stronger adhesion. Amorphous Se with graphene has comparable interface strength (0.34 J m), but electron exchange in this system is slightly distinct from monoclinic Se. The electronic characteristics and bonding mechanisms are different for monoclinic and amorphous Se with graphene as they activate graphene via surface charge doping divergently. The implications of these interfacial physicochemical attributes on electrode performance have been discussed. Our findings highlight the complex electrochemical phenomena in Se interfaced with graphene, which may profoundly differ from their "free" counterparts.
我们对晶体硒和非晶硒与石墨烯之间的界面强度和键合机制进行了全面的第一性原理密度泛函理论（DFT）分析，这两者在储能应用中是很有前景的组合。还对非晶硅与石墨烯以及晶体硒与传统铝集流体之间进行了对比界面分析。单斜晶硒与石墨烯（0.43 J/m²）和非晶硅与石墨烯（0.41 J/m²）的界面强度在数值上相似。虽然这两种材料（晶体硒、非晶硅）通过范德华力在石墨烯上松散结合，但非晶硅/石墨烯的界面电子交换更高。通过比较石墨烯界面上的势能台阶和电荷转移（Δ）进一步阐述了这一点。晶体硒在三维铝集流体上的界面强度更高（0.99 J/m²），表明附着力更强。非晶硒与石墨烯具有相当的界面强度（0.34 J/m²），但该体系中的电子交换与单斜晶硒略有不同。单斜晶硒和非晶硒与石墨烯的电子特性和键合机制不同，因为它们通过表面电荷掺杂以不同方式激活石墨烯。讨论了这些界面物理化学属性对电极性能的影响。我们的研究结果突出了硒与石墨烯界面处复杂的电化学现象，这可能与它们“游离”状态下的对应物有很大不同。
