Your link points to a more complete article, which claims that it will be practical to recycle waste heat from a laptop computer into electrical power. That could certainly enhance the energy efficiency of a laptop. But I wouldn't hold my breath waiting to get more than 10% of my energy back that way . . .
You’re ALWAYS going to have heat loss and irreversible processes in each conversion. The heat “lost” from the battery as the laptop runs is only a part of the battery’s energy from the stored electrical charge: further, this heat MUST be removed from the case (electronics) or they (literally) fry. This heat convertor-to-electricity also has losses itself, so it cannot turn all of the inbound heat to useful energy, which cannot in turn be turned back into the stored chemical battery energy.
So the net energy in the “outside-the-case” heat converter source is less than that inside the case in the chemical energy in the battery to begin with: and the net electrical/chemical energy available back into the laptop’s battery is less than what came out the first time.
The concept could extend the battery life a bit, but an heat outside source is required. Maybe we’ll be able to burn candles to run a laptop AND read the book? 8<)