Summary

Natural rubber has been identified as a suitable material to be served as an electrolyte in various devices. Its polymeric structure is suitable for provision of ion motion after modifying and complexing with a suitable salt and solvents. Natural rubber from Malaysia has been investigated by several research groups for different types of batteries by grafting polymethylmethacrylate (MG NR- methyl grafted natural rubber).
In this study, methyl grafted Sri Lankan natural rubber will be used to prepare polymer electrolytes with different salts. Mainly, solvent casting method will be used to obtain thin, mechanically stable films. Initial studies will be done to fine tune the composition to utilize the electrolytes for applications. Properties of the samples will evaluated using numerous techniques including Electrochemical Impedance Spectroscopy, DC polarization Test, X Ray Diffraction, Scanning Electron Microscopy and Fourier Transform Infra Red Spectroscopy. Samples having appreciable conductivities will be used for fabricating batteries and super capacitors. Regarding batteries, priority will be given for non lithium batteries. Sri Lankan graphite as well as conducting polymers will also be used to fabricate batteries. Both types of super capacitors, namely electric double layer and redox will be prepared with Sri Lankan graphite and suitable conducting polymers respectively.
Performance of devices will be evaluated using Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Galvanostatic Charge Discharge test. In addition, the stability of the devices will also be monitored.

Objectives

1. Investigating proper preparation methods and strategies to enhance conductivity of Sri Lankan natural rubber based electrolytes
   As no group has involved in making electrolytes using Sri Lankan natural rubber, one of the major issues that is planned to address is choosing the appropriate preparation conditions that will result in good quality electrolytes. International scientific community who has involved in research activities on rubber based electrolytes has reported low ionic conductivities of those systems. So, attempts will be put forward to improve the conductivities of Sri Lankan rubber based electrolytes. Attention will be given to environmental friendly and low cost approaches.
2. Fabricating non-lithium batteries
   At present, there is a high demand for power due to rapid use of diverse applications. Batteries have been playing a major role to fulfill this unending requirement and among them, lithium batteries are now in the front. As far as lithium is concerned, it is one of the hazardous elements and also it is not environmental friendly. This is a serious issue for a country like Sri Lanka specially at the time of disposal. So, it is very essential to move towards non lithium batteries.
3. Fabricating super capacitors
   Super capacitors have recently received a global interest in the field of power and energy as they are known to bridge the gap between batteries and conventional capacitors. One of the major problems faced with super capacitors at the moment is their high cost. With respect to the type of electrodes, there are two categories namely electric double layer capacitors (EDLCs) and redox capacitors. Carbon based electrodes are used in EDLCs where as conducting polymer and transition metal oxide based electrodes are used for redox capacitors. Both have their merits and demerits. Only few Sri Lankan research groups including ours are engaging in research activities on using Sri Lankan graphite for electrodes in EDLCs. Priority has been given to liquid electrolytes but we have used gel polymer electrolytes in those EDLCs. As per the literature reviews, only our group is involved with work related to redox capacitors in Sri Lanka. For them too, we are using gel polymer electrolytes. In this study, one of the investigations will be done using Sri Lankan natural rubber based electrolytes with Sri Lankan graphite. It may result super capacitors completely based on Sri Lankan raw materials.
4. Uplifting research culture in Wayamba University of Sri Lanka (WUSL)
   Being relatively a new university, research facilities available in WUSL are not at a satisfactory level. As a result, research engagement is not upto the standard level. More facilities are required to do advance research. University is still not in a position to provide sufficient financial assistance for purchasing high tech equipments, for assisting research students etc. Therefore, external assistance is very much required to uplift the research culture in the university.
5. Producing human resources enrich with sound theoretical and practical knowledge
   It is very much needed to have personal with a good knowledge in theoretical aspects and practical aspects related to various fields in order to carry forward research activities. In this project it is expected to enrich knowledge mainly on use of natural rubber based electrolytes and their use in science and technology field.

Major Equipment Facilitated by Grant