Supramolecular Polymer Intertwined Free-Standing Bifunctional Membrane Catalysts for All-Temperature Flexible Zn–Air Batteries
Nayantara K. Wagh, Sambhaji S. Shinde, Chi H. Lee, Sung‐Hae Kim, Dong‐Hyung Kim, Han‐Don Um, Sang Uck Lee, Jung‐Ho Lee
Abstract
Abstract Rational construction of flexible free-standing electrocatalysts featuring long-lasting durability, high efficiency, and wide temperature tolerance under harsh practical operations are fundamentally significant for commercial zinc–air batteries. Here, 3D flexible free-standing bifunctional membrane electrocatalysts composed of covalently cross-linked supramolecular polymer networks with nitrogen-deficient carbon nitride nanotubes are fabricated (referred to as PEMAC@NDCN) by a facile self-templated approach. PEMAC@NDCN demonstrates the lowest reversible oxygen bifunctional activity of 0.61 V with exceptional long-lasting durability, which outperforms those of commercial Pt/C and RuO 2 . Theoretical calculations and control experiments reveal the boosted electron transfer, electrolyte mass/ion transports, and abundant active surface site preferences. Moreover, the constructed alkaline Zn–air battery with PEMAC@NDCN air–cathode reveals superb power density, capacity, and discharge–charge cycling stability (over 2160 cycles) compared to the reference Pt/C + RuO 2 . Solid-state Zn–air batteries enable a high power density of 211 mW cm −2 , energy density of 1056 Wh kg −1 , stable charge–discharge cycling of 2580 cycles for 50 mA cm −2 , and wide temperature tolerance from − 40 to 70 °C with retention of 86% capacity compared to room-temperature counterparts, illustrating prospects over harsh operations.