Power plants based on principles of Rankine Cycle.

Almost all thermal power plants around the world using coal as fuel are based on principles of Rankine cycle. Maximum cycle efficiency is 40 to 42%. The heat transfer between various stages of medium i.e. water, steam & condensed steam and the electricity produced determine cycle efficiency .Even with the modern developments in metallurgy, heat loss during heat transfer cannot be eliminated. Modern engineering design and various construction techniques like CCCP may yield 45 to 50% efficiency. Is it possible to cross the threshold of poor performance /cycle efficiency beyond 50%? It would be a boon to power producers when coal deposits around the world are depleting. Is there any research being done or development in present technology?