The synthesis of graphene/PVDF composite binder and its application in high performance MnO2 supercapacitors

To effectively fabricate and use MnO2 in supercapacitors, a graphene/polyvinylidene fluoride (PVDF) composite binder has been designed and fabricated. The 5% CBE shows higher specific capacitance (220 F g(-1)) than the 5% PBE (202 F g(-1)) at 0.5 A g(-1) with an identical amount of graphene, which is physically mixed in the manufacturing process of electrodes. It has been found that the graphene content in the composite binder has a significant effect on electrochemical activities of electrodes and capacitors manufactured from these methods. A maximum specific capacitance of 220 F g(-1) can be obtained with graphene mass ratios up to 5 wt%. In addition, the 5% CBE shows excellent cycling stability that is over 90.07% of the initial specific capacitance and is retained after 1000 cycles. The improved electrochemical performance can be attributed to the formation of chemical bond between graphene and PVDF in the composite binder, which provides an effective electron pathway by bridging MnO2 particles in the electrodes that leads to rapid electron transfer and low charge transfer resistance. (C) 2015 Elsevier B.V. All rights reserved.