No abstract

Four novel ZnII coordination polymers, [Zn(btc)0.5(H2O)] n (1), {[Zn(btc)0.5(4,4‘-bpy)0.5(H2O)]·1.5H2O} n (2), {[Zn2(H2btc)2(4,4‘-bpy)4]·H2O} n (3), [Zn(H2btc)(bpe)] n (4) [H4btc = biphenyl-3,3‘,4,4‘-tetracarboxylic acid, 4,4‘-bpy = 4,4‘-bipyridine, and bpe = 1,2-bis(4-pyridyl)ethane], have been synthesized by hydrothermal reactions. Single-crystal X-ray structural analysis reveals that the four polymers exhibit different novel bilayer architectures. Complex 1 possesses a bilayer structure in which two helical layers are further pillared by (btc)4- ligands into a two-dimensional (2D) bilayer network. Complex 2 is an unusual 2D double-layered supramolecular motif generated by hydrogen bonding interactions of two single-layered networks. Complex 3 displays a 2D supramolecular bilayer network formed by the one-dimensional {[Zn2(H2btc)2(4,4‘-bpy)4]·H2O} n polymer. Complex 4 features a 2D double-layered framework in which two puckering single layers are linked by μ2-carboxylato groups of (H2btc)2- anions. The diverse structures illustrate rational adjustment of the second ligand, and the pH value is a good method to further design bilayer metal−organic compounds with novel structures and properties. In addition, the thermal stabilities and photoluminescence properties of 1−4 were also studied.

Aqueous zinc‐ion battery (AZIB) has become a promising candidate in grid energy storage due to its low cost, environmental friendliness, and high safety. However, AZIB usually suffers from uncontrollable zinc deposition and dendrite growth as well as hydrogen evolution and passivation on the surface of zinc anode. To address the above issues, a unique 3D Zn alloy foam anode built from Zn–Sn–Pb alloy in 3D Cu foam is constructed by a facile hot dipping method. The proposed 3D Zn alloy anode, through introducing elements Sn and Pb, enhances the hydrogen evolution overpotential, reduces the corrosion current, greatly mitigates the self‐corrosion in the electrolyte, and efficiently inhibits the growth of Zn dendrite during cycling. Importantly, such Zn alloy engineering together with a 3D Cu foam current collector enables highly stable Zn storage properties. The full cell assembled using the proposed 3D Zn alloy anode and MnO2 nanosheet cathode exhibits superior reversible capacity (103.4 mAh g−1) and excellent cycling stability (capacity retention of 87% over 4000 cycles) at 1.8 A g−1.

A three-dimensionally ordered macroporous (3DOM) Li3V2(PO4)3/C cathode material with small-sized macropores (50-140 nm) is successfully synthesized using a colloidal crystal array. The 3DOM architecture is built up from fully densely sintered Li3V2(PO4)3/C nanocomposite ceramics particles. Such a 3DOM Li3V2(PO4)3/C micrometer sized particle combines the advantages of both Li3V2(PO4)3 nanocrystal and micrometer sized particle. The resultant 3DOM Li3V2(PO4)3/C nanocomposite exhibits a stable and highly reversible discharge capacity up to 151 mA g(-1) at 0.1 C, and an excellent high-rate capability of 132 mA g(-1) at 5 C in the voltage range of 3.0-4.4 V. Compared to the corresponding bulk nanocomposite, the 3DOM Li3V2(PO4)3/C cathode exhibits a significantly improved high-rate performance, which promises new opportunities in the development of high energy and high power lithium-ion batteries.