A quasi-solid-state Li-ion capacitor based on porous TiO₂ hollow microspheres wrapped with graphene nanosheets

The quasi-solid-state Li-ion capacitor is demonstrated with graphene nanosheets prepared by an electrochemical exfoliation as the positive electrode and the porous TiO₂ hollow microspheres wrapped with the same graphene nanosheets as the negative electrode, using a Li-ion conducting gel polymer electrolyte. This device may be the key to bridge the gap between conventional lithium-ion batteries and supercapacitors, meanwhile meeting the safety demands of electronic devices.