Room-Temperature Micropillar Growth of Lithium–Titanate–Carbon Composite Structures by Self-Biased Direct Current Magnetron Sputtering for Lithium Ion Microbatteries

Here, an unidentified type of micropillar growth is described at room temperature during conventional direct-current magnetron sputtering (DC-MS) deposition from a Li₄Ti₅O₁₂+graphite sputter target under negative substrate bias and high operating pressure. These fabricated carbon–Li₂O–TiO₂ microstructures consisting of various Li₄Ti₅O₁₂/Li₂TiO₃/Li_x TiO₂ crystalline phases are demonstrated as an anode material in Li-ion microbatteries. The described micropillar fabrication method is a low-cost, substrate independent, single-step, room-temperature vacuum process utilizing a mature industrial complementary metal–oxide–semiconductor (CMOS)-compatible technology. Furthermore, tentative consideration is given to the effects of selected deposition parameters and the growth process, as based on extensive physical and chemical characterization. Additional studies are, however, required to understand the exact processes and interactions that form the micropillars. If this facile method is further extended to other similar metal oxide–carbon systems, it could offer alternative low-cost fabrication routes for microporous high-surface area materials in electrochemistry and microelectronics.