Hollow nickel-cobalt-manganese hydroxide polyhedra via MOF templates for high-performance quasi-solid-state supercapacitor

Constructing high specific area and porous micro-nano frameworks is suitable for fast electrons/ions transport, which motivates us to design hollow polyhedra with multi-order structure. However, the synthesis route of hollow polyhedra is still restricted due largely to the complexity and high cost. Herein, the finding in rational design and one-pot hydrothermal synthesis of porous hollow nickel-cobalt-manganese hydroxide (NiCoMn-OH) polyhedra is reported, using zeolitic imidazolate framework-67 (ZIF-67) as the templates. The ultrathin edge-to-face stacking nanosheets construct a three-dimensional multi-order hollow polyhedral structure with internal nanoporous channels, which can stimulate electron/ion transfer. Toward the application in supercapacitor, the NiCoMn-OH electrode presented superior capacitance performance (1654.5 F g−1 at 1 A g−1) and excellent rate performance (58.5% retention at 30 A g−1) in a three electrode alkaline system. Moreover, the quasi-solid-state NiCoMn-OH//AC device was also fabricated, exhibiting excellent capacitance of 121.5 F g−1 at 1 A g−1, high energy density of 43.2 Wh kg−1 at a power density of 0.79 kW kg−1, and outstanding capacitance retention (100% retention after 10,000 cycles). Also, the suitable energy supply capacity of NiCoMn-OH electrode was further validated, via utilizing two quasi-solid-state NiCoMn-OH//AC devices to trigger light-emitting diode (LED) bulbs.