Flexible aqueous ammonium-ion full cell with high rate capability and long cycle life

Aqueous full cell based on non-metal NH4+ ions redox reactions has been reported recently owing to NH4+ ions as charge carriers with advantages of abundant resources, light weight, eco-friendly and fast diffusion capability. However, the exploration of NH4-ions full cell is still in its infancy. Despite the aforementioned unique properties of the aqueous NH4-ions full cell, there is almost no reported about the flexible NH4-ions full cell so far. Developing novel electrodes with highly reversible NH4-ions accommodation capability underlies the construction of high-performance full cells. Here, we first demonstrate a novel flexible aqueous ammonium-ion full cell with high rate capability and long cycle life consisted of urchin-like NH4V4O10 coated on carbon fiber cathodes and polyaniline nanorods grown on carbon fiber anodes in (NH4)2SO4 aqueous solution. A high specific capacity up to 167 mA h g−1 at a current density of 0.1 A g−1, excellent rate capability with a specific capacity of 54 mA h g−1 at 1 A g−1 and an ultralong cycle life with a high capacity retention are achieved. Meanwhile, the NH4-ion full cell shows good flexibility with well-maintained electrochemical performances at different deformation states. This work may shed a light on developing flexible aqueous NH4-ion cells.