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 (NH 4 + )-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 (PF 6 - ) intercalation chemistry in graphite cathode and NH 4 + intercalation behavior in PTCDI (3,4,9,10-perylenetetracarboxylic diimide) anode. This new battery configuration successfully circumvented the reduction susceptibility of NH 4 + and the lack of mature NH 4 + -rich cathodes for NH 4 + ion batteries (AIBs). The customized organic NH 4 + 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 NH 4 + reduction.