A 2.75 V ammonium‐based dual‐ion battery

The popular metal-ion batteries (MIBs) suffer from environmental and economic issues because of their heavy dependency on nonrenewable metals. Here, we propose a metal-free ammonium (NH4+ )-based dual-ion battery with a record-breaking operation voltage of 2.75 V. The working mechanism of this sustainable battery involves the reversible anion (PF6- ) intercalation chemistry in graphite cathode and NH4+ intercalation behavior in PTCDI (3,4,9,10-perylenetetracarboxylic diimide) anode. This new battery configuration successfully circumvented the reduction susceptibility of NH4+ and the lack of mature NH4+ -rich cathodes for NH4+ ion batteries (AIBs). The customized organic NH4+ electrolyte endows the graphite||PTCDI full battery with durable longevity (over 1000 cycles) and a high energy density (200 Wh kg-1 ). We show that the development of AIBs should be high-voltage-oriented while circumventing low operation potential to avoid NH4+ reduction.