▶ Ultrapure hydrogen at a stable rate of 25 mL/min was produced from a novel solid-state NaBH 4 composite. ▶ No mechanical control system was in need to maintain the stable production of hydrogen from this solid NaBH 4 chemical-hydride system. ▶ A cellular phone was successfully powered at 2 W for 2 h by a PEMFC stack fed with the produced hydrogen. ▶ The generated hydrogen could be successfully converted to electric energy by the PEMFC stack to recharge a 3.7 V/1100 mAh Li-ion battery in 2 h. Hydrolysis of sodium borohydride (NaBH 4) is a promising method for on-board hydrogen supply to polymer electrolyte membrane fuel cells (PEMFC). This article presents an attempt to design a novel solid-state NaBH 4 composite, which is made up of NaBH 4 powder, Co 2+/IR-120 catalyst and silicone rubber, for hydrogen generator. The silicone rubber can act as a stabilizer in the solid-state NaBH 4 composite because of its surface hydrophobicity leading to reduced diffusion rate of water into the composite. The solid-state NaBH 4 composite can produce hydrogen stably near 25 mL min −1 for at least 2 h without employment of any mechanical control system. Using the hydrogen generated from the solid-state NaBH 4 composite, a 2 W PEMFC stack is successfully operated to power a cellular phone.