Harvesting Air and Light Energy via “All‐in‐One” Polymer Cathodes for High‐Capacity, Self‐Chargeable, and Multimode‐Switching Zinc Batteries

Abstract

Aqueous rechargeable Zinc (Zn)–polymer batteries are promising alternatives to prevalent Li‐ion cells in terms of cost, safety, and rate capability but they suffer from limited specific capacity in addition to poor environmental adaptability. Herein, air and light are successfully utilized from external environments in single near‐neutral two‐electrode Zn batteries to enable remarkably improved electrochemical performance, fast self‐charging, and switchable multimode‐operation from Zn–polymer to Zn–air cells. This system is enabled by a well‐designed polyaniline‐nanorod‐array based “all‐in‐one” cathode combining reversible redox capability, oxygen reduction activity, and photothermal‐responsiveness. The initiative design allows perfect integration of multiple energy harvesting from ambient “air” and light, energy conversion, and storage in one single cathode. Thus, it can act as an efficient light‐assisted electrically‐rechargeable Zn–polymer cell featuring the highest specific capacity of 430.0 mAh g−1 among all existing polymer cathodes. Without external power sources, it can be self‐charged to deliver a high discharging capacity of 363.1 mAh g−1 by concurrently harvesting chemical energy from air and light energy for only 20 min. It can also switch to a light‐responsive Zn–air battery mode to surmount the output capacity limit of Zn–polymer battery mode for continued electricity supply.

An Air-Rechargeable Zn/Organic Battery with Proton Storage

“…This is also reflected by the discharge capacity of the Zn/BQPH battery during the air-charging process. The Zn/BQPH battery delivers a discharge capacity of 128 mAh g –1 after oxidation for only 4 h. When the air-charging time reaches 10 h, the Zn/BQPH battery exhibits a high discharge capacity of 351 mAh g –1 (Figure b), which is higher than the cases of previously reported air-rechargeable AZBs. ,,,− However, the discharge capacity of Zn/BQPH batteries degrades when the oxidation time exceeds 10 h since more basic zinc sulfate is formed (Figure S30).…”

Protonating imine sites of polyaniline for aqueous zinc batteries

“…Polyaniline (PANI), probably the most studied conducting polymer, is a promising cathode material for aqueous zinc batteries, 1–7 mainly due to its good electrical conductivity, high electrochemical reactivity/reversibility, and low cost. 8–22 Depending on the oxidation degree, three forms of PANI have been recognized: reduction state (leucoemeraldine), half oxidation state (emeraldine), and oxidation state (pernigraniline) (Scheme 1). 23 The redox transitions of leucoemeraldine/emeraldine and emeraldine/pernigraniline result in the two typical redox couples of PANI during electrochemical applications.…”

Proton Chemistry Induced Long‐Cycle Air Self‐Charging Aqueous Batteries

“…Even at a low current density of 0.2 A g −1 with self‐charging time of 8 h, the Pb/PTO battery also delivers an accumulated discharge capacity of 14 472 mAh g −1 after 100 cycles (Figures 4e and S15). The excellent self‐charging cycle stability of Pb/PTO batteries is superior to other previously reported cases of air‐rechargeable AMBs based on near‐neutral electrolytes (Figure 4f and Table S1) [5a–c, 17, 18] …”