Armoring Black Phosphorus Anode with Stable Metal-Organic-Framework Layer for Hybrid K-Ion Capacitors

HighlightsThe ultrathin metal-organic-framework (MOF) interphase layer with high mechanical/chemical stability was in situ grown on black phosphorus nanosheets (BPNSs).MOF interphase layers as an ordered porous and robust protective layer can facilitate K ion diffusion and accommodate the volume change of the electrode.Benefiting from the improved reaction kinetics and enhanced electrode stability, the BPNS@MOF anode for potassium-ion capacitors exhibits outstanding cycle performance. AbstractPotassium-ion capacitors (KICs) are promising for sustainable and eco-friendly energy storage technologies, yet their slow reaction kinetics and poor cyclability induced by large K-ion size are a major obstacle toward practical applications. Herein, by employing black phosphorus nanosheets (BPNSs) as a typical high-capacity anode material, we report that BPNS anodes armored with an ultrathin oriented-grown metal-organic-framework (MOF) interphase layer (BPNS@MOF) exhibit regulated potassium storage behavior for high-performance KICs. The MOF interphase layers as protective layer with ordered pores and high chemical/mechanical stability facilitate K ion diffusion and accommodate the volume change of electrode, beneficial for improved reaction kinetics and enhanced cyclability, as evidenced by substantial characterizations, kinetics analysis and DFT calculations. Consequently, the BPNS@MOF electrode as KIC anodes exhibits outstanding cycle performance outperforming most of the reported state-of-art KICs so far.

Automated summary

The study demonstrates that black phosphorus nanosheets (BPNSs) with an ultrathin metal-organic-framework (MOF) interphase layer exhibit regulated potassium storage behavior for high-performance potassium-ion capacitors (KICs). The protective MOF interphase layer with ordered pores and high chemical/mechanical stability facilitates K ion diffusion and accommodates electrode volume change, leading to improved reaction kinetics and enhanced cycle stability. The BPNS@MOF electrode as KIC anodes demonstrates outstanding cycle performance exceeding that of most current KICs.