Metal‐Organic Framework Derived Ni₂P/C Hollow Microspheres as Battery‐Type Electrodes for Battery‐Supercapacitor Hybrids

Abstract

Nickel phosphide (Ni 2 P/C) hollow microspheres were synthesized via a facile two-step route based on metal-organic framework (MOF) precursors. Unlike direct phosphating the MOF by calcination that would damage the MOF structure and that would form multiple phases, solvothermal method was able to convert the Ni-based MOF to one-pure-phase nickel phosphide with the MOF skeleton maintained, as suggested by XRD, XPS, and SEM. When using as the battery-supercapacitor hybrids electrode material, the optimized Ni 2 P/C exhibited the specific capacity 670.4 C/g (1676 F/g) at 1 A/g in a threeelectrode system, and a maximum energy density 42.74 Wh/kg at 764.23 W/kg in an asymmetric supercapacitor. It also delivered an energy density of 35.39 Wh/kg at 7000 W/kg with the rate capability retention of 92 % after 5000 cycles. The high specific surface area and the increased amount of electrochemically active sites endowed by the unique morphology, together with the low charge transfer resistance all contribute to the excellent electrochemical performance of the Ni 2 P/C material. These also indicate that solvothermal method is feasible in converting MOF to metal phosphide for the application in energy storage and conversion systems.[a] Prof.

Porous SnO2/C Nanofiber Anodes and LiFePO4/C Nanofiber Cathodes with a Wrinkle Structure for Stretchable Lithium Polymer Batteries with High Electrochemical Performance

“…[ 37–40 ] The C 1s XPS spectrum in Figure 2c includes peaks corresponding to CC, CO, and C=O bonds at 284.1, 285.4, and 288.4 eV, respectively. [ 41–44 ] The highest intensity of the CC peak among the three peaks confirms the carbonization of PVA during heat‐treatment. Thermogravimetric analysis (TGA) was carried out in order to confirm the amount of C decomposed by PVA in the structure, as shown in Figure 2d.…”

Hierarchical Carbon Nanowire/Ni@MnO2 Nanocomposites for High‐Performance Asymmetric Supercapacitors

“…In Figure S8 b of the Supporting Information, the core‐level Ni 2p spectrum features two typical peaks at 855.7 (Ni 2p 3/2 ) and 873.4 eV (Ni 2p 1/2 ) with two satellite peaks at 861.2 and 879.1 eV. After deconvolution analysis, the two typical peaks can be split into four peaks, among which those at 852.4 and 870.9 eV are assigned to the Ni 0 state and those at 855.6 and 873.2 eV are associated with Ni 2+ [19, 54, 55] . Furthermore, only five elements (C, N, O, Ni, and Mn) without other impurities can be observed in the full survey spectrum of CC/N‐CNWs/Ni@MnO 2 (Figure S9 of the Supporting Information), which is identical to the EDS (mapping) results.…”

Synthesis of Co3O4/Carbon Heteroaerogels with Ultrahigh Capacitance via Polyethyleneimine Intercalation of Co2BIM4 Nanosheets

“…The capacitance performance of the Co 2 BIM 4 ‐Co 3 O 4 /NC electrode are also much higher than the electrodes based on MOF or MOF‐derived oxides and oxides/carbon (Table S1), such as Ni‐MOF (1127 F g −1/ 0.5 A g −1 ), [15] Ni‐MOF‐based NiO (116 F g −1 /1 A g −1 ), [39] Ni‐MOF‐derived Ni 2 P@C (1676 F g −1 /1 A g −1 ), [40] Co‐MOF‐derived PC/Co 3 O 4 (423 F g −1 /1 A g −1 ), [41] Co‐MOF‐derived Co 9 S 8 /NS‐C (734 F g −1 /1 A g −1 ), [42] ZIF‐9@polyaniline (710 F g −1 /1 A g −1 ), [43] ZIF‐67@Mn‐ZIF‐derived Co 3 O 4 @MnO 2 (413 F g −1 /0.5 A g −1 ) [44] . The capacitance performance of the Co 2 BIM 4 ‐Co 3 O 4 /NC electrode should be ascribed to the synergistic effects.…”

“…Figure 5b shows the galvanostaticc harge/discharge behaviors of the three electrodes at 1Ag À1 .S everal slanting plateaus have been observed, which is consistent with the CV results. Clearly, the voltage plateaus of the Co 2 BIM 4 -Co 3 O 4 /NC heteroaerogele lectrode is more obvious the other two electrodes during charg- The capacitance performance of the Co 2 BIM 4 -Co 3 O 4 /NC electrode are also much higher than the electrodes based on MOF or MOF-derived oxides and oxides/carbon (Table S1), such as Ni-MOF( 1127 Fg À1/ 0.5 Ag À1 ), [15] Ni-MOF-based NiO (116 Fg À1 / 1Ag À1 ), [39] Ni-MOF-derived Ni 2 P@C (1676Fg À1 /1 Ag À1 ), [40] Co-MOF-derived PC/Co 3 O 4 (423 Fg À1 /1 Ag À1 ), [41] Co-MOF-derived Co 9 S 8 /NS-C (734 Fg À1 /1 Ag À1 ), [42] ZIF-9@polyaniline (710 Fg À1 / 1Ag À1 ), [43] ZIF-67@Mn-ZIF-derived Co 3 O 4 @MnO 2 (413 Fg À1 / 0.5 Ag À1 ). [44] The capacitance performance of the Co 2 BIM 4 -Co 3 O 4 /NC electrode should be ascribed to the synergistic effects.…”