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Metal–organic framework (MOF) derived nanoarchitectures have special features, such as high surface area (SA), abundant active sites, exclusive porous networks, and remarkable supercapacitive performance when compared to traditional nanoarchitectures. Herein, we propose a viable strategy for the synthesis of hollow manganese nickel selenide spheres comprising nanosheets supported on the nickel foam (denoted as MNSe@NF) from the MOF. The MNSe nanostructures can demonstrate enriched active sites, and shorten the ion-electron diffusion pathways. When the MNSe@NF electrode is used as a cathode electrode for a hybrid supercapacitor, the electrode reflected impressive supercapacitive properties with a high capacity of 325.6 mA h g−1 (1172.16 C g−1) at 2 A g−1, an exceptional rate performance of 86.6% at 60 A g−1, and remarkable longevity (3.2% capacity decline after 15 000 cycles). Also, the assembled MNSe@NF∥AC@NF hybrid supercapacitors employing activated carbon on the nickel foam (AC@NF, anode electrode) and MNSe@NF (cathode electrode) revealed an impressive energy density of 66.1 W h kg−1 at 858.45 W kg−1 and an excellent durability of 94.1% after 15 000 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • The FeNi 2 S 4 @Co 9 S 8 nanoarrays wrapped by reduced graphene oxide synthesized. • The reduced graphene oxide acts as a framework around the nanoarrays to hinder the agglomeration. • The as-made material reflects high supercapacitive performance. • A hybrid supercapacitor shows good energy density. Mixed metal sulfides (MMSs) combined with carbonaceous materials are considered effective electrode materials for supercapacitors owing to their satisfactory capacity and rate capability. Herein, lollipop-like FeNi 2 S 4 @Co 9 S 8 nanoarrays wrapped by reduced graphene oxide on nickel foam (NF\L-FNSCS-rGO) are manufactured for a hybrid supercapacitor. Briefly, FeNi layered double hydroxide (FeNi-LDH) nanowires are first prepared by a hydrothermal route. Afterward, zeolitic imidazolate framework-67 (ZIF-67) nanocages welding on the top of FeNi-LDH nanowires are designed at room temperature. Then, sulfidation of the obtained nanoarrays in the presence of thioacetamide leads to the formation of FeNi 2 S 4 @Co 9 S 8 nanostructures. Finally, the L-FNSCS-rGO nanoarrays were constructed on NF by coating graphene oxide (GO) sheets on amino-propyltriethoxysilane (APTES)-modified FeNi 2 S 4 @Co 9 S 8 nanoarrays, followed by reduction of the GO by thermal treatment. Benefiting from this peculiar architecture, the designed NF\L-FNSCS-rGO possesses sufficient electrochemical active sites as well as developed diffusion pathways for electrolyte ions. Therefore, the NF\L-FNSCS-rGO reveals a large capacity of 1308C/g, splendid rate performance (e.g., 1093.5C/g at 36 A/g), and high longevity (93.75% retention after 8500 cycles). The corresponding hybrid supercapacitor device (NF\L-FNSCS-rGO//NF\activated carbon (AC)) delivers a good energy density of 68.85 Wh kg−1 at 860.7 W kg−1 with the NF\L-FNSCS-rGO (cathode electrode) and NF\activated carbon (AC) (anode electrode), demonstrating the potential for the real applications. More importantly, the new structural design can be extended to the fabrication of other materials for extensive applications. [ABSTRACT FROM AUTHOR]

Hollow MnFe 2 O 4 nanocubes assembled by CoS 2 nanosheets are fabricated by an effective strategy for hybrid supercapacitors. [Display omitted] • Hollow MnFe 2 O 4 nanocubes were prepared by calcination of MnFe-PBA. • CoS 2 nanosheets were formed on MnFe 2 O 4 nanocubes by hydrothermal method. • CoS 2 acts as the structure protector to prevent the collapse of MnFe 2 O 4. • The as-prepared nanomaterial shows good electrochemical properties. • A hybrid supercapacitor delivers high energy density. Even though the transition metal oxides (TMOs) are theoretically favorable for supercapacitors, the low electrical conductivity and durability hinder their major practical application. Designing TMOs with innovative nanostructures and unique properties is an effective strategy to overcome these limitations and boost their electrochemical properties. Considering this, in this research, we design hollow MnFe 2 O 4 nanocubes assembled by CoS 2 nanosheets (designated as HMFO-CSN) and evaluate its supercapacitive performance where it is used as a cathode electrode in the hybrid supercapacitors. The nanostructuring strategy used here includes three steps (i) MnFe-Prussian blue analogue (MnFe-PBA) nanocube formation, (ii) calcination of the MnFe-PBA to produce MnFe 2 O 4 hollow structures, and (iii) growing CoS 2 nanosheets on the product through the hydrothermal process to get the final product, i.e., HMFO-CSN. The hollow MnFe 2 O 4 nanocube which acts as the effective skeleton can fasten electron transportation and ion diffusion. Meanwhile, the existing porous CoS 2 nanosheet is not only served as an effective outer layer to enhance conductivity but also acts as a structure protector to prevent the collapse and degradation of inner MnFe 2 O 4 hollow nanocube during stability test. Benefiting from such merits, the as-synthesized nanomaterial shows a capacity of 894C g−1 at 1 A g−1 with a rate capability of 76.2% (681.25C g−1 at 48 A g−1), and excellent 90.5% capacity retention at 12 A g−1 after 10,000 cycles. Furthermore, the hybrid supercapacitor made of HMFO-CSN (cathode electrode) and activated carbon (AC, anode electrode) delivers an energy density of 63.75 Wh kg−1 at 850 W kg−1 with high longevity of 88.5% after 10,000 cycles at 12 A g−1. The developed synthetic method may offer new inspirations for the fabrication of high-performance electrode materials with advanced structures for various energy-related applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanosheet assembled hollow α-MnS@Co 3 S 4 spheres (NSH-MCS) were fabricated by an effective strategy. • The NSH-MCS sample was chosen as an efficient positive electrode for hybrid supercapacitors. • A hybrid supercapacitor is constructed using NSH-MCS and activated carbon with desirable energy density. Nanostructured mixed metal sulfides (MMSs) have emerged as a prominent kind of material for use in the fields of energy storage thanks to their intrinsic safety and good theoretical specific capacity. In this paper, nanosheet assembled hollow α-MnS@Co 3 S 4 spheres (NSH-MCS) with special morphology are synthesized and evaluated as an effective positive electrode for the hybrid supercapacitors. The synthesis process starts with the growth of the Co-based zeolitic imidazolate framework (ZIF-67) nanosheets onto manganese-glycerate (Mn-G) solid spheres. The direct sulfidation of the Mn-G@ZIF-67 nanostructures leads to the formation of NSH-MCS. The special structure can provide rich mass/electron transfer channels, meanwhile prevent the accumulation of nanosheets. Taking advantage of these great merits, the NSH-MCS based electrode discloses appealing electrochemical features including an impressive capacity value of 283.3 mAh/g (1019.9C/g) at 1 A/g with desired rate performance of 81.5% at 25 A/g and significant longevity of 92.7% over 10,000 cycles at 15 A/g. Also, a hybrid supercapacitor assembled with NSH-MCS positive electrode and AC (activated carbon) negative electrode proves desirable performance, such as a good energy density (54.9 Wh/kg at 753 W/kg) and excellent longevity of 90.5% after 10,000 cycles at 15 A/g. The straightforward strategy introduced in this paper can open an effective avenue for the fabrication of various MMSs for other applications. [ABSTRACT FROM AUTHOR]