Synthesis of Porous 3D Metallic Current Collectors for High Performance Lithium Batteries

Conventional thin film lithium ion batteries are built on a planar design where electrode material is coated on to a conducting current collector substrate. Contact resistance between the current collector and the electrode always hinders the overall performance of the battery. In order to better utilize the electrode material, 3D current collector architectures with nanoscale roughness have been proposed which would increase the electrode-current collector surface contact area thereby significantly reducing interfacial resistance. The nanoporous current collector configuration is one of several 3D designs which have shown high potential for the development of high energy and high power microbatteries. We present here a scalable process for the synthesis of three dimensional porous metallic current collectors with conformal graphene coating on the surface. One step chemical vapor deposition technique has been used for controlled etching and simultaneous graphene growth on the surface of metals such as copper and stainless steel. The 3D structures can be directly used as a cathode in lithium ion battery as graphene has lithium intercalating capability. The structural and morphology of the current collector/electrode hybrid structures were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) analysis, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The contribution of 3D current collectors resulted in excellent cyclic stability and capacity compared to using conventional 2D configuration.