Intramolecular Hydrogen Bonds Enhanced Quinone-Based Anode for High-Performance Aqueous Proton Batteries.

Abstract

Aqueous proton batteries (APBs), utilizing redox-active organic materials as the minimal hydrate proton charge carriers, have emerged as promising candidates for next-generation energy-storage. However, conventional quinone-based electrode inclines to suffer from critical limitations, including electrode dissolution and sluggish reaction kinetics in strong acid electrolytes. To overcome this challenge, a quinone-based polymer (HMND) material with intermolecular hydrogen bonds (HBs) was designed as an anode for APBs. This material forms HBs (C═O⋯N─H) between O in ─C═O and H in ─NH₂ that can not only significantly enhance the cycling stability of the organic electrode but also endow it with outstanding rate capability by accelerating proton transfer through the Grotthuss mechanism. The proton insertion/extraction mechanism has been verified through DFT, in situ/ex situ Raman spectra, and FT-IR. Furthermore, the full APBs coupled with MnO₂@GF cathode delivers a long lifespan of 42 000 cycles with a capacity decay rate of only 0.0018% per cycle at 8 A g^-1, along with an excellent rate performance (212.5 mAh g^-1 at 1 A g^-1, 91.4 mAh g^-1 at 70 Ag^-1). It consistently showcases outstanding electrochemical performances even under extreme conditions in a frozen electrolyte at -60 °C, implying great potential for energy storage applications under extreme temperature scenarios.