Electrochemistry and morphology evolution of carbon micro-net films for rechargeable lithium ion batteries

The highly ordered carbon micro-net films (CMNFs) have been fabricated through patterning and pyrolyzing SU-8 photoresist. They are structurally characterized by transmission electron microscopy and selected area electron diffraction, and they exhibit the mixed phases of both crystalline and disordered carbon. An initial discharge capacity of as large as 350 mu Ah/cm(2) is observed, and the pseudocapacitance-like charge/discharge curves with reversible capacity of about 100 mu Ah/cm(2) are shown in the following cycles. From the images of scanning electron microscopy, the originally three-dimensional architecture of CMNFs is well kept after long-term electrochemical cycling. The kinetic parameters such as solid electrolyte interphase resistance, charge transfer resistance, and chemical diffusion coefficients of Li+ insertion are estimated by alternate-current impedance measurements. The CMNFs are expected to be promising electrodes for future three-dimensional microbatteries.