Chromium Chevrel phase sulfide (CrCPS : CrxMo6S8-y) was investigated as the cathode in lithium rechargeable batteries. This compound had a triclinic unit cell in a wide range of chromium composition. Electrochemical cells based on the intercalation of lithium into both stoichiometric and nonstoichiometric CrCPS were examined by a long-term cycling in deep discharge depth at a relatively high constant current density. The nonstoichiometric Cr1.3Mo6S7.7 showed a long cycle life more than 1000 cycles in the voltage range from 2.7 V to 1.5 V except for the first cycle and an energy density of at least 140 Wh kg(-1) of active material. Almost no change of crystal structure before and after 1000 cycles contributed to such an excellent cycle performance. From the open circuit voltage (OCV) measurement and X-ray diffraction analysis we propose the reaction models and also estimate the lithium intercalation sites for triclinic CrCPS.