Atomic Engineering Catalyzed MnO2 Electrolysis Kinetics for a Hybrid Aqueous Battery with High Power and Energy Density

• Published in: Advanced materials (Weinheim) Vol. 32; no. 25; pp. e2001894 - n/a
• Main Authors: Chao, Dongliang, Ye, Chao, Xie, Fangxi, Zhou, Wanhai, Zhang, Qinghua, Gu, Qinfen, Davey, Kenneth, Gu, Lin, Qiao, Shi‐Zhang
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.06.2020
• Subjects: aqueous batteries; catalyzed kinetics; Charge transfer; Density functional theory; Electric potential; Electrolysis; electrolysis reaction; Electron energy loss spectroscopy; Electron states; Electronegativity; Energy dissipation; Energy storage; Fine structure; Flux density; high power/energy density; Manganese dioxide; Materials science; Metal air batteries; Nickel; Reaction kinetics; Storage batteries; Voltage; Zinc-oxygen batteries; Zn‐ion batteries
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202001894

Research interest and achievements in zinc aqueous batteries, such as alkaline Zn//Mn, Zn//Ni/Co, Zn–air batteries, and near‐neutral Zn‐ion and hybrid ion batteries, have surged throughout the world due to their features of low‐cost and high‐safety. However, practical application of Zn‐based secondary batteries is plagued by restrictive energy and power densities in which an inadequate output plateau voltage and sluggish kinetics are mutually accountable. Here, a novel paradigm high‐rate and high‐voltage Zn–Mn hybrid aqueous battery (HAB) is constructed with an expanded electrochemical stability window over 3.4 V that is affordable. As a proof of concept, catalyzed MnO2/Mn2+ electrolysis kinetics is demonstrated in the HAB via facile introduction of Ni2+ into the electrolyte. Various techniques are employed, including in situ synchrotron X‐ray powder diffraction, ex situ X‐ray absorption fine structure, and electron energy loss spectroscopy, to reveal the reversible charge‐storage mechanism and the origin of the boosted rate‐capability. Density functional theory (DFT) calculations reveal enhanced active electron states and charge delocalization after introducing strongly electronegative Ni. Simulations of the reaction pathways confirm the enhanced catalyzed electrolysis kinetics by the facilitated charge transfer at the active O sites around Ni dopants. These findings significantly advance aqueous batteries a step closer toward practical low‐cost application. A paradigm high‐rate and high‐voltage affordable Zn–Mn hybrid aqueous battery (HAB) is constructed with an electrochemical stability window over 3.4 V. Imposing power of 19 kW kg−1 and energy of 650 Wh kg−1 are demonstrated. Spectra techniques and theoretical calculations reveal the origin of the concomitant power and energy densities, via catalyzed kinetics in an aqueous battery.