SU8 Derived Glassy Carbon for Lithium Ion Batteries

Glassy carbon (GC) is an amorphous yet sp rich allotrope of carbon that has received a lot of attention as an electrode material in Li ion batteries. In this contribution we explore the microstructural, thermal and mechanical properties of GC derived from the pyrolysis of lithographically patterned SU8, which is the most common precursor polymer in CMEMS (carbon microelectromechanical systems). Microstructural characterization of CMEMS carbon in terms of interlayer separation of the characteristic turbostratic (randomly arranged) graphene layers, which influences the mechanism of lithiation and accompanying swelling and heating during battery operation, is carried out employing electron microscopy. Mechanical properties of the thus obtained GC are also investigated using nanoindentation for films, and microcompression tests for micropillars. Rapid heating/cooling of the miniaturized GC structures due to their relatively large surface area is demonstrated by Joule heating of a carbon nanowire (CNW) suspended onto CMEMS walls.