Electrochemical study of two structurally related compounds $$\hbox {FeVMoO}_{7}$$ FeVMoO 7 and $$\hbox {CrVMoO}_{7 }$$ CrVMoO 7 synthesized by sol–gel method

Abstract

$$\hbox {FeVMoO}_{7}$$ and $$\hbox {CrVMoO}_{7}$$ phases were synthesized by sol–gel method for the first time and used as promising cathode materials for Lithium ion batteries. Effortless and flexible procedure for the preparation of $$\hbox {FeVMoO}_{7}$$ and $$\hbox {CrVMoO}_{7}$$ via a facile sol–gel method was developed. The structure, morphology and the electrochemical properties have been studied by X-ray diffraction (XRD), scanning electronic microscope (SEM) and galvanostatic charge-discharge test measurements. Study of these compounds as electrode materials was motivated by the three-dimensional structure and the redox couples of Fe, V and Mo. The first cycle discharge capacity values for $$\hbox {FeVMoO}_{7}$$ and $$\hbox {CrVMoO}_{7}$$ phases were 284 $$\hbox {mAhg}^{-1}$$ and 264 $$\hbox {mAhg}^{-1}$$ , respectively, in the voltage range of 3.2–1.5 V. The discharge capacity of $$\hbox {FeVMoO}_{7}$$ was 160 $$\hbox {mAhg}^{-1}$$ after 20 cycles. Synopsis FeVMoO $$_{7}$$ and CrVMoO $$_{7}$$ phases have been studied as electrode materials for the first time. Sol–gel method was adopted, for the first time, to synthesize these phases and the phases exhibit good electrochemical behavior. Electrochemical lithium insertion into three dimensional phases of FeVMoO $$_{7}$$ and CrVMoO $$_{7}$$ is feasible and good cycling behavior was observed.