Facile and large scale combustion synthesis of α-CoMoO4: Mimics the redox behavior of a battery in aqueous hybrid device

• A cobalt molybdate based asymmetric hybrid device has been fabricated.
• Facile and large scale combustion synthesis of α-CoMoO4 is demonstrated.
• Specific capacitance of 105 F/g is obtained in aqueous electrolyte.
• The extracted energy density of the system is 14.5 Wh/kg.

We have made an investigation on cobalt molybdate (α-CoMoO4) as cathode material for aqueous hybrid system, in which the α-CoMoO4 positive material was prepared by a facile and scalable unique solution combustion synthesis (SCS) technique in air at ambient atmosphere. The α-CoMoO4 is stable at ambient temperature. The structural, morphological and pseudocapacitive properties of the α-CoMoO4 were studied by XRD, Raman, SEM and cyclic voltammetry. The XRD and Raman analysis evidenced the formation of pure crystalline α-CoMoO4 phase. The material α-CoMoO4 is reproducible using the simple combustion technique and the process scalability has been determined. The asymmetric hybrid device (AC vs. α-CoMoO4) (activated carbon denoted AC) exhibited good electrochemical performance in terms of specific capacitance (105 Fg−1) and energy density (14.5 Wh kg−1). The asymmetric device shows very good cycling stability, with 98% of initial capacitance retained after 4000 cycles. The α-CoMoO4 closely mimics the redox mechanism that contributes to the obtained specific capacitance.