Microsupercapacitors (integrated electrochemical supercapacitors) for on-chip electrochemical energy storage are fast becoming a critical component of many self-powered and sensor systems. While thin film batteries and micro-batteries have been commercialized, they suffer from limited lifetime and low power density. On the other hand, microsupercapacitors may be a viable replacement for microbatteries due to their very high power density and long cycle life. In fact, very high power densities can be achieved in microsupercapacitors due to shorter ion diffusion distances between electrodes compared to conventional supercapacitors, absence of separator which enhances ion diffusion, and compatibility with IC fabrication methods. We are developing material synthesis and microfabrication strategies to improve the performance of microsupercapacitors. We are also developing, multifunctional supercapacitors for self-powered sensors, and testing approaches for integrating them with thin film electronics.