RJD2440ST1 is a rechargeable lithium-ion coin cell battery designed for memory backup and power supply in wearable electronic and IoT devices. It features a nominal voltage of 3.7 VDC (operating range 4.2 VDC to 3.0 VDC) with a nominal capacity of 150 mAh and minimum capacity of 140 mAh. The cell employs a graphite anode and lithium nickel manganese cobalt oxide cathode, supporting standard discharge currents of 28 mA and maximum discharge currents of 280 mA, with a maximum internal resistance of 800 mO. It charges via constant current/constant voltage (CCCV) method at 4.2 VDC ± 0.03 V with a charging current of 0.5 CA and charging time under 3.0 hours. The battery operates reliably across -20°C to +60°C and is certified to UL1642 (MH28281), making it suitable for long-life, high-power applications requiring compact form factors and reliable performance in portable electronics.