Patents
Materials commonly used as electrolyte mediums are either strongly acidic/alkaline or low molar mass organic solvents, such as EC, EMC, DMC, DEC, VC, PC, etc. the several cons, some of the primary limitations of these systems are attributed to their corrosive nature, being prone to leakage and evaporation, flammability and safety issues, environmental toxicity, weight and design restrictions, performance degradation and self-discharge. The key players involved in the Li-ion rechargeable battery business barring a few start-ups for example still rely heavily on liquid electrolytes albeit technical reliability and safety concerns. Polymer electrolytes are projected to address multiple issues related to devising performance (leakage, evaporation, corrosion, safety, stability, laminations, sealing, design and weight limitations), factors such as relatively low ionic conductivity, the ability of polymer electrolytes to operate with highly reactive electrodes such as lithium over a wider temperature range without deterioration in the charge capacity and electrolyte properties, the high interfacial electrode-electrolyte impedances, adhesion, lamination and wetting are still a major technological challenge and far from practical realisation. The invention relates to high-ionic conductivity electrolyte compositions of semi-interpenetrating polymer networks and their nanocomposites as quasi-solid/solid electrolyte matrix for energy generation, storage and delivery devices, particularly for hybrid solar cells, rechargeable batteries, capacitors, electrochemical systems and flexible devices. The present invention utilises select chemistry and strategy to modify the polymeric architectures, forming semi-interpenetrating polymer networks and their nanocomposites, electrolyte compositions with tailored morphology, reduced crystallinity, thermal and dimensional stability, enhanced film-forming capability, reducing/limiting the use of plasticisers prone to leakage and evaporation, and high ionic charge transport capability of polyether systems while addressing the gaps and bottlenecks. The end product in the process is a new series of high-ionic conductivity electrolyte compositions of semi-interpenetrating polymer networks and their nanocomposites as quasi-solid/solid electrolyte matrix which can find potential use in the next generation energy conversion, storage and delivery devices, in particular for hybrid solar cells, rechargeable batteries, capacitors, electrochemical systems and flexible devices. The high ionic conductivity achieved is in the range of 10"4- 10"3Scm"1 at ambient temperatures without using low molecular weight plasticisers such as ethylene carbonates, ethyl methyl carbonates, and so on, which is a significant achievement. Further, the electrolyte matrices are thermally very stable up to 1500 C.