The Aqueous Rechargeable proton-ion insertion Battery: a new concept of eco-sustainable energy storage – AqReBat

In this project, we propose to investigate the replacement of alkali-metal ion carriers (Li+, Na+, …) commonly used in aqueous rechargeable cation-ion insertion batteries by the proton-ion, with the main ambition to demonstrate a new concept of aqueous rechargeable battery that is eco-sustainable, low cost and long life. For this, we intend to rely on the exploitation of the pair of TiO2/MnO2 electrode materials that are both earth-abundant, inexpensive, and non-toxic metal oxides, and also capable to deliver high energy and power densities in the presence of a mild non-corrosive buffered aqueous electrolyte. This original idea of a aqueous rechargeable proton-ion insertion battery is based on a recent discovery that allowed us to demonstrate for the first time that it was possible to massively, rapidly and reversibly insert protons within a mesoporous amorphous TiO2 electrode immersed in a neutral pH buffered aqueous solution, a process that we were also able to verify, very recently, as being transposable to other metal oxides such as MnO2.

Regardless of this main objective of demonstrating the proof-of-concept of a rechargeable aqueous proton-ion insertion battery, a second objective will be to better understand the underlying fundamental aspects that govern proton insertion/disinsertion processes coupled with charge transfers at the interfaces of TiO2 and MnO2 metal oxides, including a particular attention to the influence of the nature and constituents of the aqueous buffer.
Given the expected performance compounded with many other qualities (safety, low cost, long life, environmentally friendly), the aqueous rechargeable proton-ion insertion TiO2/MnO2 battery has the potential to not only be beneficial to the field of large-scale energy storage systems connected to power plants, but also to strongly interest the fast growing market of electric vehicles.

The impact and benefits of the project are also scientific since if we are successful in validating the concept of aqueous rechargeable proton insertion battery, there is a probability that it will induce a paradigm-shifting opportunity in the scientific community for the design and development of a wide range of other proton-ion insertion batteries. Moreover, the knowledge that will be gained in understanding the proton storage mechanism in neutral aqueous buffers or in highly concentrated buffered electrolytes such as water-in-salts is likely to promote and stimulate the development of aqueous batteries with improved proton insertion, but also to provide a new way of thinking about the fundamental role played by electrolyte in aqueous batteries.