Those eggs you might have had for breakfast? They’re not just food — they may be the key to longer-running batteries in your devices. Scientists at MIT and Tsinghua University have developed a nanoparticle battery electrode whose egg-like design is built to last. Their invention, which houses a shape-changing aluminum “yolk” in a titanium dioxide cell, can go through charging cycles without degrading like the graphite electrodes in conventional power packs. That could improve not…