Micropore-facilitated surface-dominated pseudocapacitive storage in MOF-derived hollow nano-cuboids enabled by in-situ Zn-sacrificed strategy

Herein, we report a novel metal–organic frameworks (MOF)-derived nanomaterial, this is hollow nano-cuboids composed of NiCoP particles and nanocarbon, which is enriched in appropriate micropores induced by in-situ Zn-sacrificed strategy (NiCoP@C(Zn)). Such abundant micropores (∼0.5 nm, larger than the radius of OH−) can supply more ion shuttle channels at multi-directions, greatly-reducing the longitudinal migration time in the hollow structure, resulting in a rather high ion diffusion coefficient (∼10−8 cm2 s−1). This combined with hollow topology show the marked electrolyte-accessibility recognized by experimental and density functional theory (DFT) results, which can adequately-expose the electrochemically active sites, thus birthing a surface-dominated pseudocapacitive behaviors towards high-rate response and high-capacity storage. Due to the robust structural merits and pore character as well as their synergy, the NiCoP@C(Zn) electrode can realize a rather stable cyclability (over 10,000 cycles). Further, we construct the pouch-type supercapacitor based on NiCoP@C(Zn) cathode, which delivers a relatively-good energy output (35.2 Wh kg−1), superior to those of some previously-reported asymmetric supercapacitors. Remarkably, such pouch device can exhibit the triple-high properties, including high mechanical reliability, high safety and high availability in real-word application. This work successfully-discloses the influence of well-matched micropores on pseudocapacitive charge storage, and opens new horizons of developing a high-performance electrode nanomaterial.