Organic Ammonium Ion Battery: A New Strategy for a Nonmetallic Ion Energy Storage System.

Nonmetallic ammonium (NH4 + ) ion batteries are promising candidates for large-scale energy storage systems, which have the merit of low molar mass, sustainability, non-toxicity and non-dendrite. Herein, for the first time, we introduce the novel organic ammonium ion batteries (OAIBs). Significantly, a manganese-based Prussian white analogue (noted as MnHCF) as cathode exhibits a reversible capacity of 104 mAh g-1 with 98 % retention over 100 cycles. We further demonstrate the electrochemical performance of the NH4 + ion full cell, which delivers a reversible capacity of 45 mAh g-1 with a broad electrochemical window. Combining ex situ XPS, ex situ XRD results and electrochemical properties, the NH4 + ion storage mechanism of MnHCF in a non-aqueous electrolyte is clearly revealed. This work verifies the feasibility of employing NH4 + ions as charge carriers in organic energy storage systems and provides new insights for designing organic nonmetallic ion batteries with broad electrochemical windows and high energy density.