Enhanced Energy Storage Performance of 3D Hybrid Metal Sulfides via Synergistic Engineering of Architecture and Composition

Abstract

Optimizing the architecture and tailoring the phase composition are useful approaches to increasing electrochemical capacitor energy storage performance. In this work, a novel three-dimensional (3D) hybrid nickel cobalt sulfide wrapped in ultrathin carbon layer (nickel cobalt sulfides@C) was rationally designed and constructed with varied hollow and porous dendritic superstructures. The morphology evolution process has been demonstrated in detail by adjusting the Co/ Ni ratio and reaction duration. Different phases of nickel cobalt sulfides@C can be tailored after sulfuration, enabling the systematic exploration of the energy storage performance with synergistic engineering of architecture and composition. Benefiting from the 3D dendritic superstructures with porous/hollow nature, tunable chemical composition, abundant phase boundaries, enhanced specific surface area, and highly conductive carbon layer matrix, (Ni,Co) 9 S 8 /NiS/Ni 3 S 2 @C yields an outstanding specific capacity of 856.6 C g −1 at the current density of 1 A g −1 . Furthermore, the assembled asymmetric supercapacitor device presents higher energy density of 70.6 Wh kg −1 and power density of 8873.5 W kg −1 with excellent cycling stability. This synthetic strategy highlights the crucial role of synergistic engineering of architecture and chemical composition in practical energy storage, and the as-designed functional materials will be a competitive and promising candidate for robust electrochemical capacitor energy storage and other applications.

A Redox-Additive Electrolyte and Nanostructured Electrode for Enhanced Supercapacitor Energy Density

“…As shown in Table , the FG//NC ASCs having a redox additive show superior energy densities as compared to the other works that also used KFCN as the redox additive Ni-Co-O@RGO//AC ASC (39.5 Wh kg –1 ) in 1 M KOH + 0.01 M KFCN, MWCNTs/MnO 2 //Fe 2 O 3 ASC (54.4 Wh kg –1 ) in 1 M Na 2 SO 4 + 0.3 M KFCN, CoS/AC nanocomposite//AC ASC (44.2 Wh kg –1 ) in 1 M KOH + 0.08 M KFCN, rGO/TiO 2 nanosheet//rGO/TiO 2 nanosheet SC (15.5 Wh kg –1 ) in 1 M Na 2 SO 4 + 0.2 M KFCN, porous carbon//porous carbon SC (36.9 Wh kg –1 ) in 1 M Na 2 SO 4 + 0.03 M KFCN, and ZIF-67/rGO composite//ZIF-67/rGO composite SC (25.5 Wh kg –1 ) in 1 M Na 2 SO 4 + 2 M KFCN . The ASC also show a higher energy density than the other binary Ni–Co electrodes in KOH reported recently, including NiCo 2 -LDHs@MXene/rGO//MXene/rGO, FeNiP@CoNi-LDH//porous carbon, MnO 2 @NiCo-LDH/CoS 2 //AC, Mn-doped Ni-Co LDH//PANI-derived carbon, (Ni,Co) 9 S 8 /NiS/Ni 3 S 2 @C//AC, Zn-Ni-Co-O@Co-Ni LDH//N-doped graphene, and Zn-Co-Ni LDH//AC . In summary, the use of the unique three-dimensional nanostructure NC positive electrode and the KFCN/KOH electrolyte gives excellent supercapacitor performance, especially the outstanding energy density.…”

Dual-Carbon Engineering of Nanosized (Ni0.28Co0.72)1–xS for Li+ Storage with Enhanced Rate Capability and Stability

“…Furthermore, the adjustment of Ni/Co molar ratio could also induce the phase evolution of NiCo sulfides and oxides. 23,24 MOFs are the ideal precursors for metal sulfides; 25 composition. 26,27 In this approach, a bimetal-MOF-derived ternary metal sulfide was designed by Xiangxin Guo's group, 28 and the obtained porous CoNi 2 S 4 -based compound demonstrated excellent Li + storage performance.…”

Carbon Nanolayer-Wrapped Mesoporous TiO2–B/Anatase for Li+ Storage

“…Hao Ren’s group fabricated double-shelled anatase/TiO 2 –B hollow microspheres with the core of TiO 2 –B and the shell of anatase phases via a sequential templating route, and the composite displayed a high specific discharge capacity (215.4 mA h g –1 at 1 C = 335 mA h g –1 ) . Second, designing and constructing mesoporous structures are essential for increasing the specific area and improving the chemical reaction activity . Moreover, the mesopores are beneficial to enhance the contact area between the electrolyte and the electrode, elevating the Li + transportation during the lithiation/delithiation process. , Considerable efforts have been dedicated for investigating the mesoporous structures.…”

“…9 Second, designing and constructing mesoporous structures are essential for increasing the specific area and improving the chemical reaction activity. 23 Moreover, the mesopores are beneficial to enhance the contact area between the electrolyte and the electrode, elevating the Li + transportation during the lithiation/delithiation process. 24,25 10,21 which is difficult to exist at high temperature.…”