Nzzz 295-5100 MT621 Rechargeable Battery for Citizen Eco-Drive Watches – Compatible with 295-51/295-5100, BP10, E000, E001, E010, E011 Watch Capacitor & Panasonic Battery NiMH

Your watch has a Citizen caliber E111 movement which uses a MT621 rechargeable battery (Citizen part number 295-5100). These are available on Amazon here for US $15.82. A local jeweler should be able to change the battery for a nominal charge. If you want to do it yourself, there's a video here that shows how it's done.