Carbon-reinforced Ni3S2/Ti3C2Tx MXene composite as an anode for superior-performance lithium-ion capacitors.

Lithium ion capacitors (LICs) are a new generation of energy storage devices that combine the super energy storage capability of lithium ion batteries with the satisfactory power density of supercapacitors. The development of high-performance LICs still faces great challenges due to the unbalanced reaction kinetics at the anode and cathode. Therefore, it is an inevitable need to enhance the electron/ion transfer capability of the anode materials. In this paper, to obtain a superior-rate and high-capacity Ni3S2-based anode, highly conductive Ti3C2Tx MXene sheets were introduced to sever as the carrier of Ni3S2 nanoparticles and simultaneously an amorphous carbon layer which coats onto the surface of Ni3S2 nanoparticles was in-situ generated by the carbonization of dopamine reactant. The as-synthesized Ni3S2/Ti3C2Tx/C composite exhibits a high specific surface area (112.6 m2/g) because of the addition of Ti3C2Tx that can reduce the aggregation of Ni3S2 nanoparticles and the in-situ generated amorphous carbon layer that can suppress the growth of Ni3S2 nanoparticles. The Ni3S2/Ti3C2Tx/C anode possesses a remarkable reversible discharge specific capacity (626.0 mAh/g under 0.2 A/g current density), which increases to 1150.8 mAh/g after 400-cycle charge/discharge measurement at the same measurement condition indicating eminent cyclability, along with superior rate capability. To construct a superior-performance LIC device, a sterculiae lychnophorae derived porous carbon (SLPC) cathode with an average discharge specific capacity of 73.4 mAh/g@0.1A/g was prepared. The Ni3S2/Ti3C2Tx/C//SLPC LIC device with optimal cathode/anode mass ratio has a satisfactory energy density ranging from 32.8 to 119.1 Wh kg-1 at the corresponding power density of 8799.4 to 157.5 W kg-1, together with a prominent capacity retention (95.5 %@1 A/g after 10,000 cycles).

Amorphous Co-Mo-S nanospheres fabricated via room-temperature vulcanization for asymmetric supercapacitors.

Ternary metal sulfides employed in supercapacitors exhibit better electrochemical performances than their counterpart oxides due to their superior conductivity. However, the insertion/extraction of electrolyte ions can lead to a significant volume change in electrode materials, which can result in poor cycling stability. Herein, novel amorphous Co-Mo-S nanospheres were fabricated through a facile room-temperature vulcanization method. It involves the conversion of crystalline CoMoO4 by reacting it with Na2S at room temperature. In addition to the conversion of the crystalline state into an amorphous structure with more grain boundaries, which is beneficial for the transport of electron/ion and can accommodate the volume change generated by the insertion/extraction of electrolyte ions, the production of more pores led to an increased specific surface area. The electrochemical results indicate that the as-prepared amorphous Co-Mo-S nanospheres had a specific capacitance of up to 2049.7F/g@1 A/g together with good rate capability. The amorphous Co-Mo-S nanospheres can be used as the cathode of supercapacitors and assembled with an activated carbon anode into an asymmetric supercapacitor possessing a satisfactory energy density of 47.6 Wh kg-1@1012.9 W kg-1. One of the prominent features exhibited by this asymmetric device is its remarkable cyclic stability, with a capacitance retention of 107% after 10,000 cycles.

Hydrothermal Synthesis of Co-Doped NiSe2 Nanowire for High-Performance Asymmetric Supercapacitors.

Co@NiSe2 electrode materials were synthesized via a simple hydrothermal method by using nickel foam in situ as the backbone and subsequently characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and a specific surface area analyzer. Results show that the Co@NiSe2 electrode exhibits a nanowire structure and grows uniformly on the nickel foam base. These features make the electrode show a relatively high specific surface area and electrical conductivity, and thus exhibit excellent electrochemical performance. The obtained electrode has a high specific capacitance of 3167.6 F·g-1 at a current density of 1 A·g-1. To enlarge the potential window and increase the energy density, an asymmetric supercapacitor was assembled by using a Co@NiSe2 electrode and activated carbon acting as positive and negative electrodes, respectively. The prepared asymmetrical supercapacitor functions stably under the potential window of 0⁻1.6 V. The asymmetric supercapacitor can deliver a high energy density of 50.0 Wh·kg-1 at a power density of 779.0 W·kg-1. Moreover, the prepared asymmetric supercapacitor exhibits a good rate performance and cycle stability.

Syntheses and crystal structures of two heterometallic iodoplumbates containing mixed-valence copper(I/II).

Mixed-valence copper(I/II) atoms have been introduced successfully into a Pb/I skeleton to obtain two heterometallic iodoplumbates, namely poly[bis(tetra-n-butylammonium) [bis(µ3-dimethyldithiocarbamato)dodeca-µ3-iodido-hexa-µ2-iodido-tetracopper(I)copper(II)hexalead(II)]], {(C16H36N)2[Cu4ICuIIPb6(C3H6NS2)2I18]}n, (I), and poly[[µ3-iodido-tri-µ2-iodido-iodido[bis(1,10-phenanthroline)copper(I)]copper(I)copper(II)lead(II)] hemiiodine], {[CuICuIIPbI5(C12H8N2)2]·0.5I2}n, (II), under solution and solvothermal conditions, respectively. Compound (I) contains two-dimensional anionic layers, which are built upon the linkages of CuII(S2CNMe2)2 units and one-dimensional anionic Pb/I/CuI chains. Tetra-n-butylammonium cations are located between the anionic layers and connected to them via C-H...I hydrogen-bonding interactions. Compound (II) exhibits a one-dimensional neutral structure, which is composed of [PbI5] square pyramids, [CuII4] tetrahedra and [CuIIN4I] trigonal bipyramids. Face-to-face aromatic π-π stacking interactions between adjacent 1,10-phenanthroline ligands stabilize the structure and assemble compound (II) into a three-dimensional supramolecular structure. I2 molecules lie in the voids of the structure.

[Pb3Cu2I10(phen)4]n: a novel organic-inorganic hybrid ferromagnetic semiconductor.

An iodoplumbate-based organic-inorganic hybrid ferromagnetic semiconductor, [Pb3Cu2I10(phen)4]n, has been solvothermally synthesized. The ferromagnetic exchange interaction is resulting from the multiple aromatic π-π stacking interactions between the adjacent phen molecules.

Poly[diaqua-tris(µ(4)-isophthalato)dilanthanum(III)].

In the title coordination polymer, [La(2)(C(8)H(4)O(4))(3)(H(2)O)(2)](n), there are two independent La(III) atoms which are coordinated differently in slightly distorted penta-gonal-bipyramidal and slightly disorted bicapped trigonal-prismatic environments. The La(III) ions are bridged by µ(4)-isophthalate ligands, forming two-dimensional layers. In the crystal structure, these layers are connected by inter-molecular O-H⋯O hydrogen bonds into a three-dimensional network.

Poly[[diaqua-bis-(µ(3)-isonicotinato-κN:O:O')bis-(µ(2)-isonicotinato-κN:O)gadolinium(III)disiliver(I)] nitrate monohydrate].

In the title compound, {[Ag(2)Gd(C(6)H(4)NO(2))(4)(H(2)O)(2)]NO(3)·H(2)O}(n), the Gd(III) ion is coordinated by eight O atoms from six isonicotinate ligands and two water mol-ecules in a distorted square anti-prismatic geometry. Two Ag(I) ions are each bonded to two N atoms from two isonicotinate ligands in a linear or bow-like fashion [N-Ag-N angles = 178.6 (2) and 147.1 (2)°]. These metal ions are connected by the isonicotin-ate ligands into a layer parallel to (010). O-H⋯O hydrogen bonds donated by the coordinated and uncoordinated water mol-ecules and intra-layer π-π stacking inter-actions between the pyridine rings [centroid-centroid distances = 3.551 (4) and 3.555 (4) Å] are observed. The layers inter-act with each other by inter-layer Ag⋯O(aqua) contacts [2.731 (4) Å] and π-π stacking inter-actions between the pyridine rings [centroid-centroid distances = 3.466 (3) and 3.516 (3) Å], resulting in the formation of a three-dimensional supra-molecular structure.

(N,N-Diethyl-dithio-carbamato-κS,S')iodido(1,10-phenanthroline-κN,N')copper(II).

The copper(II) atom in the title compound, [Cu(C(5)H(10)NS(2))I(C(12)H(8)N(2))], is chelated by the N-heterocycle and the dithio-carbamate anion in a slightly distorted tetragonal coordination. The tetragonal-pyramidal coorination is completed by the iodine atom in the apical position. One ethyl group is disordered over two positions with site occupancies of 0.31 (2) and 0.69 (2).

Bis(µ-N,N-dimethyl-dithio-carbamato-κS,S':S)bis-[(N,N-dimethyl-dithio-carbamato-κS,S')copper(II)].

In the centrosymmetric dimeric title compound, [Cu(2)(C(3)H(6)NS(2))(4)], the Cu(II) atom is five-coordinate in a square-pyramidal environment. The basal coordination positions are occupied by four S atoms from two dimethyl-dithio-carbamate ligands and the apical coordination position is occupied by an S atom also bonded to the other Cu atom.

Iodido(1,10-phenanthroline-κN,N')(piperine-1-carbodithioato-κS,S')copper(II).

In the title compound, [Cu(C(6)H(10)NS(2))I(C(12)H(8)N(2))], the Cu(II) ion is coordinated by one iodide ion, two N atoms of the phenanthroline ligand and two S atoms from the piperidyl-dithio-carbamate ligand in a distorted square-pyramidal environment.

(2,2'-Bipyridine-κN,N')iodido(pyrrol-idine-1-dithio-carboxyl-ato-κS,S')copper(II).

In the title compound, [Cu(C(5)H(8)NS(2))I(C(10)H(8)N(2))], the Cu(II) ion is coordinated by one iodide ion, two N atoms of the bipyridine ligand and two S atoms from the pyrrolidine-1-dithio-carboxyl-ate ligand in a distorted square-pyramidal environment.

(2,2'-Bipyridine-κN,N')iodido(piperidine-1-carbodithio-ato-κS,S')copper(II).

In the title compound, [Cu(C(6)H(10)NS(2))I(C(10)H(8)N(2))], the Cu(II) ion is coordinated by one iodide ion, two N atoms of the bipyridine ligand and two S atoms from the piperidine-carbodithio-ate ligand in a distorted square-pyramidal environment. π-π stacking inter-actions, with centroid-centroid distances of 3.643 (4) Å, between pyridyl rings of the bipyridyl ligands of neighbouring mol-ecules lead to chains propagating parallel to the a axis.

catena-Poly[[diiodozinc(II)]-mu-4,4'-bipyridine-kappa2N:N'].

The title compound, [ZnI2(bipy)]n (bipy is 4,4'-bipyridine, C10H8N2), has been prepared by the hydrothermal reaction of ZnI2 and bipy at 433 K. Each Zn atom is coordinated by two N atoms from two different bipy ligands and by two I atoms in a distorted tetrahedral geometry, with Zn-N distances ranging from 2.068 (7) to 2.101 (8) A and Zn-I distances ranging from 2.5471 (13) to 2.5673 (13) A. The molecular structure features a zigzag polymeric chain. Face-to-face pi-pi stacking interactions between adjacent bipy ligands stabilize the structure.

Syntheses, crystal structures, and properties of heterometallic iodoplumbates: bicubane, ribbon, and chain configurations.

Successful introduction of Cu/Ag cations into the Pb/I system has led to the formation of four unprecedented heterometallic iodoplumbates in which the common connection of PbI6 units has been remarkably altered. Also, interesting long-lived fluorescence properties have been found.