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.