Reprinted from September/October 2017 issue of IEEE Power & Energy magazine By Xiaosong Hu, Changfu Zou, Caiping Zhang, and Yang Li IMAGE LICENSED BY INGRAM PUBLISHING Technological Developments in Batteries Digital Object Identifier 10.1109/MPE.2017.2708812 Date of publication: 17 August 2017 52 ieee power & energy magazine 1540-7977/17©2017IEEE september/october 2017