Atomic layer deposition of Al2O3 on organic potassium terephthalate with enhanced K-storage behavior for K-ion batteries

Abstract

Organic carbonyl compounds were regarded as one of the promising anode materials in potassium-ion (K-ion) batteries, mainly due to their environmental friendliness, flexibility as well as low cost. Nevertheless, the low initial coulombic efficiency and the side reactions with high-active electrolyte restrict its further application. Herein, atomic layer deposition (ALD) methodology was initially introduced in K-ion batteries by coating aluminum oxide (Al2O3) layer on organic potassium terephthalate (K2TP) anode materials. K2TP electrode materials were obtained by a simple ball-milling methodology, and then, they were coated by Al2O3 layer with different thicknesses. The results suggested that suitable coating layer can stabilize the electrode materials and depress the side reactions. The initial coulombic efficiency (CE) could be enhanced, and the as-prepared sample can keep 110 mAh g−1 over 100 cycles at the current density of 220 mA g−1, with improved fast charge–discharge properties. These findings are of significance for surface modification in large-scale energy storage.