Modulation of the structural diversity of diphenylalanine-based assemblies by molecular modification and solvent alteration has been extensively explored for bio- and nanotechnology. However, regulation of the structural transition of assemblies based on this minimal building block into tunable supramolecular nanostructures and further construction of smart supramolecular materials with multiple responsiveness are still an unmet need. Coassembly, the tactic employed by natural systems to expand the architectural space, has been rarely explored. Herein, we present a coassembly approach to investigate the morphology manipulation of assemblies formed by N-terminally capped diphenylalanine by mixing with various bipyridine derivatives through intermolecular hydrogen bonding. The coassembly-induced structural diversity is fully studied by a set of biophysical techniques and computational simulations. Moreover, multiple-responsive two-component supramolecular gels are constructed through the incorporation of functional bipyridine molecules into the coassemblies. This study not only depicts the coassembly strategy to manipulate the hierarchical nanoarchitecture and morphology transition of diphenylalanine-based assemblies by supramolecular interactions but also promotes the rational design and development of smart hydrogel-based biomaterials responsive to various external stimuli.

The commercial applications of MnO in lithium ion batteries (LIBs) are greatly restricted because of the low electrical conductivity and poor cycling stability at high current density. To overcome these drawbacks, mesoporous MnO@C networks were designed and synthesized via an improved bake-in-salt method using NaCl as the assistant salt, and without the protection of inert gas. The added NaCl plays a versatile role during the synthetic process, including the heat conducting medium, removable hard template and protective layer. Because of the homogeneous distribution of MnO nanoparticles within the carbon matrix, the as-prepared MnO@C networks show excellent cycling stability in LIBs. After cycling for 950 times at a current density of 1 A g, the discharge capacity of the as-prepared MnO@C networks is determined to be 754.4 mA h g, showing superior cycling stability as compared to its counterparts. The valuable and promising method, simple synthetic procedure and excellent cycling stability of the as-prepared MnO@C networks makes it a promising candidate as the potential anode material for LIBs.

MnS has been attracting more and more attentions in the fields of lithium ion batteries (LIBs) because of its high energy density and low voltage potential. In this paper, we present a simple method for the preparation of urchin-like γ-MnS microstructures using l-cysteine and MnCl2 · 4H2O as the starting materials. The urchin-like γ-MnS microstructures exhibit excellent cycling stability (823.4 mA h g−1 at a current density of 500 mA g−1, after 1000 cycles). And the discharge voltage is about 0.75 V, making it a good candidate for the application as the anode material in LIBs. SEM, TEM, and XRD were employed to inspect the changes of the active materials during the electrochemical process, which clearly indicate that the structural pulverization and reformation of the γ-MnS microstructures play important roles for the maintenance of the electrochemical performance during the charge/discharge process.

Among the transition metal oxides, the Mn3O4 nanostructure possesses high theoretical specific capacity and lower operating voltage. However, the low electrical conductivity of Mn3O4 decreases its specific capacity and restricts its application in the energy conversion and energy storage. In this work, well-shaped, octahedron-like Mn3O4 nanocrystals were prepared by one-step hydrothermal reduction method. Field emission scanning electron microscope, energy dispersive spectrometer, X-ray diffractometer, X-ray photoelectron spectrometer, high resolution transmission electron microscopy, and Fourier transformation infrared spectrometer were applied to characterize the morphology, the structure, and the composition of formed product. The growth mechanism of Mn3O4 nano-octahedron was studied. Cyclic voltammograms, galvanostatic charge–discharge, electrochemical impedance spectroscopy, and rate performance were used to study the electrochemical properties of obtained samples. The experimental results indicate that the component of initial reactants can influence the morphology and composition of the formed manganese oxide. At the current density of 1.0 A g−1, the discharge specific capacity of as-prepared Mn3O4 nano-octahedrons maintains at about 450 mAh g−1 after 300 cycles. This work proves that the formed Mn3O4 nano-octahedrons possess an excellent reversibility and display promising electrochemical properties for the preparation of lithium-ion batteries.

Pseudocapacitive materials can synergistically achieve the aim of both high energy as well as high-power density. However, the cycling stability is usually not satisfactory. To overcome this drawback, a carbon coating method is employed. Herein, we report a simple one-step method for the fabrication of Co 3 V 2 O 8 @C composite structures. Such Co 3 V 2 O 8 @C anode materials exhibit superior long cycle performance, which can deliver a discharge capacity of ∼835 mAh g −1 at a current density of 4.0 A g −1 for more than 500 cycles with a capacity retention of ∼100%. Moreover, a notable rate performance of 808, 712, 307, and 101 mAh g −1 under current densities of 5, 10, 20, and 30 A g −1 is also achieved, respectively. The experimental data clearly demonstrate that the intriguing electrochemical properties can be ascribed to the synergistic effects of pseudocapacity and carbon coating. To be specific, the pseudocapacity ensures the rate performance, while carbon coating ensures the cycling performance. This may pave the way for the development of lithium-ion batteries with high power and energy density. Moreover, this synthetic strategy can be an instructive precedent for fabricating ternary metal oxides with excellent electrochemical performance.

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In this study, a simple method was adopted for the synthesis of MnO@C nanocomposites by combining in-situ reduction and carbonization of the Mn3O4 precursor. The carbon content, which was controlled by altering the annealing time in the C2H2/Ar atmosphere, was proved to have great influences on the electrochemical performances of the samples. The relationships between the carbon contents and electrochemical performances of the samples were systematically investigated using the cyclic voltammetry (CV) as well as the electrochemical impedance spectroscopy (EIS) method. The results clearly indicated that the carbon content could influence the electrochemical performances of the samples by altering the Li+ diffusion rate, electrical conductivity, polarization, and the electrochemical mechanism. When being used as the anode materials in lithium-ion batteries, the capacity retention rate of the resulting MnO@C after 300 cycles could reach 94% (593 mAh g−1, the specific energy of 182 mWh g−1) under a current density of 1.0 A g−1 (1.32 C charge/discharge rate). Meanwhile, this method could be easily scaled up, making the rational design and large-scale application of MnO@C possible.

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