One of the significant challenges to implementing MEMS is a viable power supply strategy for autonomous devices. A suitable approach appears to be a hybrid of energy scavengers and microscopic energy storage. Lacking, however, has been microscopic energy storage technology. A new approach is underway to make batteries for MEMS. These rechargeable batteries are truly microscopic in size, are made using photolithographic processes, which allows integration. Thick film electrode structures are used to increase specific capacity and power, while minimizing cell size. Such batteries exhibit excellent power and capacity, and have tentatively shown very good cycle life. Using these batteries, integrated power supplies for MEMS can be made, including energy harvesters, batteries, and a control circuit between the two.