Energy storage performance of in-situ grown titanium nitride current collector/titanium oxynitride laminated thin film electrodes

On-chip micro-supercapacitors (MSCs) are promising ultracompact energy storage devices for wireless internet of things (IoT), micro-electromechanical system (MEMs) and portable electronics. However, most of the devices reported so far had difficulties in synchronous improvement of the energy and power densities. Here, we develop in-situ sputtering of TiN/TiOxNy laminated films with intermediate buffer layers for MSCs, using the high conductivity of TiN current collector layer to improve the rate response, the high capacitance of TiOxNy electrode layer to improve energy density, and the buffer layers to improve the interfacial bonding strength of the laminated films. It was shown that the obtained MSCs exhibited ultra-high rate capability (>500 V s−1) and remarkable cycling stability (90% capacitance retention value after 10,000 cycles), while providing high energy densities (0.7 mWh cm−3). The aforementioned superior performances suggest great potential of the laminated thin films for MSCs applications.