Transformation of Rusty Stainless‐Steel Meshes into Stable, Low‐Cost, and Binder‐Free Cathodes for High‐Performance Potassium‐Ion Batteries

Abstract

To recycle rusty stainless-steel meshes (RSSM) and meet the urgent requirement of developing high-performance cathodes for potassium-ion batteries (KIB), we demonstrate a new strategy to fabricate flexible binder-free KIB electrodes via transformation of the corrosion layer of RSSM into compact stack-layers of Prussian blue (PB) nanocubes (PB@SSM). When further coated with reduced graphite oxide (RGO) to enhance electric conductivity and structural stability, the low-cost, stable, and binder-free RGO@PB@SSM cathode exhibits excellent electrochemical performances for KIB, including high capacity (96.8 mAh g^-1 ), high discharge voltage (3.3 V), high rate capability (1000 mA g^-1 ; 42 % capacity retention), and outstanding cycle stability (305 cycles; 75.1 % capacity retention).