Exploration of low-cost microporous Fe(III)-based organic framework as anode material for potassium-ion batteries

Abstract Potassium-ion (K-ion) batteries were regarded as the promising candidate for increasingly large-scale energy storage system, mainly due to the abundant resources, low standard potential as well as fast ion transport capability. Exploring suitable anode materials that can fully accommodate the large ionic radius of K+ have been a research hotspot. Herein, a low-cost iron based metal organic framework, namely MOF-235 was initially proposed as newly anode material for K-ion batteries. After in-situ composited with multiwall-carbon tubes (MCNTs), the as-prepared MOF-235/MCNTs composite can show a specific capacity of 132 mAh g−1 over 200 cycles with remarkable rate property. The reaction mechanism was further investigated by XRD, FT-IR and XPS analysis. The superior K-storage behavior were ascribed to the large surface area of MOF-235, the enhanced electronic conductivity and the organic terephthalate moiety as the active site. These results are of significant to explore advanced anode materials for K-ion batteries.