Preparation Of Polyaniline Flexible Composites And Their Application In Energy Storage

The recent development of the wearable electronics has highlighted an urgent need for developing flexible energy storage devices.Flexible supercapacitor possesses not only characteristic of capacitor but also flexility which can satisfy the requirements of wearable electronics.Flexible electrode material and solid electrolyte are necessary for the flexible supercapacitor.Therefore,it is critical to develop relevant materials with flexiblity for flexible supercapacitors.Polyaniline(PANI)is a kind of low-cost electric conducting polymers.However,PANI is too fragile and has poor machinability.In this paper,several flexible composites were prepared and explored.First of all,PANI microspheres were successfully prepared through in situ polymerization of anilines on graphene oxide sheets.Thus,the flexible free-standing reduced graphene oxide(r GO)/PANI nanocomposite was prepared.Owing to the formation of PANI microspheres,the electrochemical capacitance of r GO/PANI nanocomposite was significantly improved.A flexible supercapacitor with excellent electrochemical performance and flexibility was further fabricated through assembling the flexible free-standing r GO/PANI nanocomposite as electrode.The supercapacitor showed high specific capacitance of0.92 F/cm~2 and its specific capacitance exhibited no obvious fading under bending state or after bending many times.Secondly,on the basis of free-standing composite,a stretchable porous polyvinyl alcohol(PVA)/PANI composite was prepared and explored.The porous structure not only contributes to the immersion of the electrolyte,but also alleviates the influence of the tensile stress on the polyaniline.Then,a supercapacitor was fabricated which exhibited a high areal capacitance of 300.9 m F/cm~2 and long-life stability of 85%capacitance retention after 10,000 charge/discharge cycles.In particular,the supercapacitor without current collector could also withstand repeated bending and stretching with limited effect on the electrochemical performance.And then a stretchable PVA/carbon nanotube(CNT)/PANI composite was prepared.The composite possessed electrical pathways which were formed by CNT framework and carbon black.The composite combines stretchability of PVA,electrical conductivity and double-layer capacitance of CNT and carbon black,and pseudocapacitance of PANI.Based on the composite,a flexible supercapacitor with the outstanding specific capacitance and high cycle life was fabricated.Importantly,a stretchable supercapacitor could be assembled by PVA/CNT/PANI composite without using carbon cloth and showed no significant energy storage capacity change at different stretching shapes or after repeated stretching/bending cycles.Finally,flexible electronics may be subjected to mechanical damage,so it is imperative to develop ideal materials with self-healing ability.Here,based on hydrogen bonding,a facile strategy was developed to fabricate a PVA gel with high stretchability,self-healing ability,recyclability and good interfacial adhesion.PVA gel could self-heal autonomously and swiftly at room temperature without any external stimulus.Furthermore,a flexible supercapacitor could be prepared based on the PVA gel and PANI.The supercapacitor possessed prominent electrochemical performance,bendability and self-healing ability.After the 5th healing,the PVA gel can reconnect the broken supercapacitor of which the capacitance retention ratio was around 87%.