There are USB-powered and Bluetooth rechargeable keyboards available to purchase. Granted, the rechargeable Bluetooth keyboards that I've seen have a condensed keyboard length. For instance, I've seen one model that's created for an iPad Mini, whereas the keyboard layout is the length of the iPad Mini; therefore be cautious if you're accustomed to a full-size keyboard as the actual keys are a bit closer together. As for using a Bluetooth keyboard made for a brand that isn't your device, there shouldn't be a problem as Bluetooth is universal (its own company, if you will) ... it might require some adjustments in the device's settings/permissions, but it should pair with any brand of tablet or smartphone. One last thing, there are different Bluetooth versions, so look at your device's manual to see what Bluetooth version it supports; the last time I've noticed, Bluetooth has 1.0, 2.0, and 3.0 versions...so if your device supports 3.0 (I believe) then any Bluetooth device would work.