Redox State-Driven Synthesis of Mesoporous and Microsphere Poly(phenylenediamine) for Transition Metal-Free and All-polymer Dual-Ion Battery.

Dual-ion batteries (DIBs) are garnering immense attention for their capability to operate without the expensive elements required by lithium-ion batteries. Phenylenediamine serves as a versatile and sustainable resource, enabling the efficient preparation of both cathode and anode materials through precise molecular control and straightforward synthesis. The innovative asymmetrical DIBs based on amine-rich poly(phenylenediamine) cathodes and imine-rich poly(phenylenediamine) anodes enable oxidative and reductive states, providing a transition metal-free rechargeable battery. The polarity difference between amine and imine redox groups in the polymeric structure resulted in a high cell voltage of 2.2 V and a specific capacity of 100 mAh g, yielding an energy density of 220 Wh kg. The radical cation generated at the cathode found stability through aromatic resonance, while the radical anion formed at the anode is supported by the quinoid structure. The exciting insights in energy storage promise a revolution with rechargeable batteries using abundant elements, offering sustainable energy solutions.