Hydrogen battery using neutralization energy

Low-cost, non-toxic and environment-friendly electrochemistry is highly needed for clean energy storage technologies. Here we propose a most simple rechargeable pH differential hydrogen battery using neutralization energy as an efficient energy storage system to utilize renewable energy and waste acid/base. The overall battery reaction can be simplified as follow: 2 H+ + 2OH(-)<-(charge) ->(discharge) 2H(2)O. This proposed hydrogen battery can deliver a theoretical specific energy of up to 250 Wh kg(-1) and a maximum energy density of up to 355 Wh L-1, very high values among aqueous battery systems. We show adding excessive amount of NaClO4 can lead to effective pH maintenance, higher coulombic efficiency, higher power and more stable cyclic performance at 9 mA cm(-2). This work offers new opportunities to develop clean and high-energy battery technologies.