Zinc doped Fe2O3 hierarchical particles for stable all-solid-state Ni-Co/Fe battery

•Zn doping enhances the electrochemical activity of Fe2O3 nanoparticles.•Morphology evolution of Zn-Fe2O3-400 has been observed during cycling test.•Using PBI-KOH polymer electrolyte, all-solid-state Ni-Co/Fe battery has been assembled.•The device shows a good capacitance retention of 85% after 6000 cycles. [Display omitted] Fast growing demands in clean energy storage devices and wearable electronics trigged the developments of all-solid-state batteries. Here, we report the synthesis of Zinc doped Fe2O3 hierarchical particles (Zn-Fe2O3 HPs) with enhanced electrochemical performance. The capacity reaches 124 mAh g−1 at 2 A g−1 after annealing treatment at 400 °C. A good cycling stability has been achieved after 1500 cycles. Interestingly, morphology evolution of active materials during the cycling test has been observed. Furthermore, all-solid-state Ni-Co/Fe batteries have been assembled using annealed Zn-Fe2O3 HPs as positive electrode, Ni and Co layered double hydroxides (NiCo-LDHs) as positive electrode and polybenzimidazole doped with KOH (PBI-KOH) as solid-state polymer electrolyte and separator. The device delivers a high specific capacity of about 72 mAh g−1 at 0.5 A g−1 based on the total mass of active materials in two electrodes. More importantly, the device shows a good cycling stability after 6000 cycles. These features endow the PBI based all-solid-state Ni-Co/Fe battery a very competitive energy storage system candidate for the wearable electronics.