Near solution-level conductivity of polyvinyl alcohol based electrolyte and the application for fully compliant Al-air battery

To coordinate the contradiction of mechanical and electrochemical properties, both polyethylene oxide (PEO) and N,N'-methylene bisacrylamide (MBA) were introduced to polyvinyl alcohol (PVA) electrolyte for Al-air battery. The doping of PEO can increase the viscosity of PVA and alleviate the interface problem with enhanced ductility. With the addition of MBA, PVA-PEO formed a stable network structure through chemical bonding, which promotes the formation of pores in the gel. The alkaline composite gel electrolyte obtains solution-level ion conductivity of 2.1 x 10(-1) S cm(-1) at room temperature. From the perspective of interface contact, the interface reaction between the gel and the aluminum foil is discussed. Meanwhile, more C-O bond is preserved and absorbs excessive protons in gel, which can reduce the evolution of H-2. The power density of the optimized gel Al-air battery coupled with pure Al is 44.5 mW cm(-2). At current density of 5 mA cm(-2), the capacity density is 1099 mAh g(-1). The excellent porous structure in the gel ensures the rapid transmission of OH- and Al(OH)(4)(-), thereby prolonging the service life of batteries. A practical watchband type flexible Al-air gel battery pack was demonstrated to drive a smart phone.