Porous surface-induced growth of HCl-doped PANi flexible electrode for high performance Zn-ion batteries with convertible storage sites

Polyaniline (PANi) has brought new enthusiasm in the field of aqueous Zn-ion batteries due to the unique nature of high conductivity, excellent structural flexibility, and fast ions de-/intercalation ability. However, the naked and densified PANi usually suffers from capacity fade and limited rate performance owing to the deprotonation of the polymer and imbalanced electron-ion transmission. Herein, a HCl-doped porous PANi electrode was prepared by electrodepositing the aniline monomer onto a porous carbon cloth (PCC), which plays an important role in elevating the loading mass and inducing porous structure of the PANi, thus enhancing the mass energy density and ions diffusion coefficient of the electrode; On the other hand, the HCl-doping could facilitate the charge delocalization and increase the conductivity of the PANi. Besides, a convertible behavior of the energy storage sites during charging-discharging processes was firstly observed for PANi, which should be responsible for the high-rate and cycling performance of the Zn-ion batteries, there is very small capacity decay from 170 mAh g −1 at 1 A g −1 to 161 mAh g −1 at 10 A g −1 , and 87 % of the initial the capacity can maintain after 2000 cycles at 5 A g −1 . Furthermore, the quasi-solid-state Zn-ion battery can also display superior performance, showing potential application of the PCC@PANi for wearable devices