Hybrid-Mechanism Synergistic Flexible Nb2O5@WS2@C Carbon Nanofiber Anode for Superior Sodium Storage.

Sodium-ion batteries (SIBs) have demonstrated remarkable development potential and commercial prospects. However, in the current state of research, the development of high-energy-density, long-cycle-life, high-rate-performance anode materials for SIBs remains a huge challenge. Free-standing flexible electrodes, owing to their ability to achieve higher energy density without the need for current collectors, binders, and conductive additives, have garnered significant attention across various fields. In this work, we designed and fabricated a free-standing three-dimensional flexible Nb2O5@WS2@C carbon nanofiber (CNF) anode based on a hybrid adsorption-intercalation-conversion mechanism of sodium storage, using electrospinning and hydrothermal synthesis processes. The hybrid structure, aided by synergistic effects, releases the advantages of all materials, demonstrating a superior rate performance (288, 248, 211, 158, 90, and 48 mA h g-1 at the current density of 0.2, 0.5, 1, 2, 5, and 10 A g-1, respectively) and good cycling stability (160 mA h g-1 after 200 cycles at 1 A g-1). This work provides certain guiding significance for future research on hybrid and flexible anodes of SIBs.

Employing a chelating agent as electrolyte additive with synergistic effects yields highly reversible zinc metal anodes.

Aqueous zinc ion batteries (AZIBs) have attracted sustained attention owing to their intrinsic safety and low cost. Unfortunately, the dendrite growth and parasitic side reactions of metallic zinc anodes severely degrade the cycling stability of the batteries and limit the practical application of AZIBs. In this work, calcium gluconate (CG), a chelating agent, as a novel electrolyte additive was introduced to tackle the thorny issue of zinc anodes in a 2 M ZnSO4 electrolyte by the synergistic effects of gluconate (GA-) anions and Ca2+ cations. Experimental characterization and computational simulations confirmed that the incorporation of GA- can not only mitigate the precipitation of Ca2+ ions, but also affect the primary solvation shell (PSS) of Zn2+ and modulate the electrode/electrolyte interfacial reaction, thereby inhibiting side reactions. Besides, trace amounts of Ca2+ cations can preferentially adsorb on the surface of the zinc anode tip, forming an electrostatic shielding shell that guides the uniform deposition of zinc ions. The Zn//Zn symmetric cells achieved a remarkably prolonged cycling lifespan ranging from 174 h to 3745 h at 6.37 mA cm-2 and 2.88 mA h cm-2 with an ultrahigh cumulative plating capacity (CPC) of about 11 900 mA h cm-2. Even at a higher current density of 5 mA cm-2 and an areal specific capacity of 5 mA h cm-2, Zn//Zn cells with the CG additive cycled for 248 h, about 5 times better than that without the CG additive. These results pave the way for the exploitation of new electrolyte additives with synergistic effects in AZIBs.

Research on the energy storage performance of laminated composites based on multidimensional co-design in a broad temperature range.

Polymer dielectrics play an irreplaceable role in electronic power systems because of their high power density and fast charge-discharge capability, but it is limited by their low stability in the temperature range of 25-200 °C. Rather than the introduction of one-dimensional fillers in polymers, we used a kind of multidimensional synergistic design to prepare Al2O3-TiO2-Al2O3/PI composites with layered structures by introducing multi-dimensional materials in polyimide (PI). In fact, the composite achieves much higher temperature stability than the pure PI film. The optimally proportioned composite has an energy density of 3.41 J cm-3 (vs. 1.48 J cm-3 for pure PI) even at 200 °C. Additionally, it reaches an impressive energy density retention of up to 90% and maintains an energy efficiency as high as 86% at 400 MV m-1 in the temperature range of 25-200 °C. The multidimensional coordination design is proposed to obtain composite films, and provides a feasible strategy in the study of polymer-based composites with high-temperature performance.

A rationally designed 3DTiO2@CdZnS heterojunction photocatalyst for effectively enhanced visible-light-driven hydrogen evolution.

Hydrogen production with higher efficiency and lower cost is of great significance for the sustainable development of energy. Zinc cadmium sulfide (CZS) is gaining more attention owing to its excellent photocatalytic properties. However, its development is greatly limited due to photogenerated charge recombination. In this work, an innovative design with a unique 3D morphology was introduced by integrating 3DTiO2 into CZS to form a novel 3DTiO2/CZS heterojunction photocatalyst. As a result, the optimized composite achieved a very high hydrogen production rate of 75.38 mmol h-1 g-1 under visible light, which is 2.4 times higher than that of the original CZS. It can also be greatly demonstrated through photoelectrochemical tests that this unique 3D morphology contributes to the effective separation of electrons and holes, thus dramatically improving the photocatalytic activity of 3DTiO2/CZS composites. The 3DTiO2/CZS composite has a rational energy band structure, which makes it more favorable for the hydrogen precipitation reaction. It is believed that such a modification strategy based on 3DTiO2 can be applied to other similar photocatalysts as well for boosting hydrogen evolution.

In Situ Growth of CdZnS Nanoparticles@Ti3C2Tx MXene Nanosheet Heterojunctions for Boosted Visible-Light-Driven Photocatalytic Hydrogen Evolution.

Using natural light energy to convert water into hydrogen is of great significance to solving energy shortages and environmental pollution. Due to the rapid recombination of photogenerated carriers after separation, the efficiency of photocatalytic hydrogen production using photocatalysts is usually very low. Here, efficient CdZnS nanoparticles@Ti3C2Tx MXene nanosheet heterojunction photocatalysts have been successfully prepared by a facile in situ growth strategy. Since the CdZnS nanoparticles uniformly covered the Ti3C2Tx Mxene nanosheets, the agglomeration phenomenon of CdZnS nanoparticles could be effectively inhibited, accompanied by increased Schottky barrier sites and an enhanced migration rate of photogenerated carriers. The utilization efficiency of light energy can be improved by inhibiting the recombination of photogenerated electron-hole pairs. As a result, under the visible-light-driven photocatalytic experiments, this composite achieved a high hydrogen evolution rate of 47.1 mmol h-1 g-1, which is much higher than pristine CdZnS and Mxene. The boosted photocatalytic performances can be attributed to the formed heterojunction of CdZnS nanoparticles and Ti3C2Tx MXene nanosheets, as well as the weakened agglomeration effects.