Materials Today Energy最新文献

Owing to the scarcity of eminent Zn-supplied cathodes, traditional aqueous Zn-ion batteries (AZIBs) still pins the hope on unstable Zn-metal anode to supply charge carriers, thus suffering from the dendrite growth and side reactions. Herein, by vanadium-manganese coupling in the spinel matrix, Zn_2.5Mn_0.5V₃O₈, a Zn²⁺ supplied cathode material with outstanding performance, has been prepared to completely get rid of the dependence on Zn-metal anode. Concretely, it delivers a high specific capacity of 355 mA•h g^-1 at 200 mA g^-1 and comforting retention of 75.7 % after 4500 cycles at 5 A g^-1. The energy storage mechanism can be summarized as two-step phase transformation in the first charge process, and the intercalation of Zn²⁺/H⁺ into host structure accomplished with a conversion reaction in the subsequent cycles. After discarding the Zn-metal anode, a “rocking-chair” AZIB of Zn_2.5Mn_0.5V₃O₈ // anthraquinone has been established, in which Zn_2.5Mn_0.5V₃O₈ exhibits the superb specific capacities (190.9 mA•h g^-1 at 200 mA g^-1) and stable cycling performance (80.8% after 1000 cycles at 200 mA g^-1 and 96.4% after 1000 cycles at 2.0 A g^-1). This work may accelerate the development of both traditional and “rocking-chair” aqueous batteries.

Notorious shuttle effect and sluggish redox kinetics as major bottlenecks have nowadays hindered the commercial implementation of lithium–sulfur batteries. The activity design of catalysts has attracted increasing attention in this realm thus far. Herein, we devise a Co-based electrocatalytic tandem (Co–N–P) encompassing (N,P)-coordinated Co single atoms and Co₂P nanoparticles for guiding the dual-directional sulfur evolution reactions. Such a Co–N–P tandem synergizes high atom utilization, large catalyst loading and smooth charge migration, thereby resulting in the high activity for dictating the Li₂S nucleation and decomposition. As a result, the full cell incorporating the Co–N–P modified separator harvests 0.1% capacity decay after 500 cycles at 1.0 C. In addition, a favorable areal capacity output of 4.2 mAh cm^–2 is obtained under a sulfur loading of 5.3 mg cm^–2. We anticipate that this work would offer insight into the hybrid catalyst design affording high activity and stability for emerging energy applications.

Self-powered sensing technology has extremely important application value in many areas, like healthcare, meteorology, internet of things (IoT) and so on. The progress of energy harvesting technology suitable for various environments is essential for the advancement of self-powered sensors. Mechanical energy has the characteristics of wide distribution, diverse forms and dispersion. The efficient collection of environmental energy is always a difficult problem in the development of self-power supply technology. In this paper, the latest research progress of mechanical energy acquisition technology, the development of self-powered sensors, the methods to improve the efficiency of energy acquisition and the key technical problems of self-powered sensors are reviewed. Especially the latest progresses in improving the output and mechanical stability of piezoelectric, magnetoelectric, triboelectric, thermoelectric nanogenerators are discussed, including nonlinear structure design, resonant tuning technology, power management circuit design, new material preparation, hybrid energy harvesting. Finally, the application prospect and future development of self-powered sensing are discussed.

Sodium-ion batteries (SIBs) are promising alternatives for Lithium-ion batteries in the field of large-scale energy storage for abundant sodium resources. Hard Carbons (HCs) are the most commonly used anode materials of SIBs for balanced electrochemical performance. The major challenges lie in low initial coulombic efficiency (ICE), insufficient reversible capacity, and the costs. Defects, pores, and graphitization degree are the main characteristics of HCs. The synergistic effects of defects and pores decide the surface adsorption distribution of electrolytes and the real electrochemical active area, which determine the solid-electrolyte interface formation process and ICE values. Sodium cluster stored in closed pores contributes to low-voltage plateau capacity with high reversibility. Suitable defect distribution on the inner wall of the closed pores ensures stable cluster formation. This review focuses on the defects and pores of HC and corresponding modification strategies, which are highlighted by their synergistic effects. We expect to offer valuable guidance for constructing next-generation HC anodes.

The strategy to boost photocatalytic activities towards CO₂ reduction and organic pollutants degradation is still a key challenge for novel Sillén-Aurivillius oxyhalides. In this work, a S-scheme heterojunction of Bi₂₄O₃₁Cl₁₀ and Bi₇Fe₂Ti₂O₁₇Cl is designed for CO₂ reduction and organic pollutants degradation. The as-synthesized 5% Bi₂₄O₃₁Cl₁₀/Bi₇Fe₂Ti₂O₁₇Cl (BOC/BFTOC-5) composites depicts an appealing CO₂ reduction and removal rate for RhB organic pollutants in comparison with pristine Bi₂₄O₃₁Cl₁₀ and Bi₇Fe₂Ti₂O₁₇Cl oxyhalides. This fascinating photocatalytic performance could be ascribed to the synergic effect of the enhanced visible light adsorption and photo-generated carriers separation derived from the Bi₂₄O₃₁Cl₁₀/Bi₇Fe₂Ti₂O₁₇Cl heterojunction. Simultaneously, the trapping experiments confirm that the main active species during the catalytic process are the photo-generated hole (h⁺) and the hydroxy free radical (·OH). This work aims at providing a S-scheme heterojunction via Bi-based oxyhalides for efficient photocatalytic activity.

Ingenious crosslinked network structure in phosphoric acid doped polybenzimidazole membranes can mitigate the mutual restriction of proton conductivity and mechanical properties. However, the complicated synthesis of tailored macromolecular crosslinker and the time-consuming post-treatment hinder their practical application as high temperature proton exchange membranes. Herein, crosslinked polybenzimidazole membranes are synthesized using small molecular crosslinker containing acidophilic quaternary ammonium groups through a one-step crosslinking strategy. After doping with phosphoric acid, the quaternary ammonium-biphosphate ion-pair coordination and the crosslinked structure result in the improved anhydrous proton conductivity, oxidation stability, and mechanical strength of the formed membranes compared to sample without crosslinking structure. Membrane with the optimized degree of crosslinking exhibits an anhydrous conductivity of 72.27 mS cm^-1 at 160 °C with a tensile strength of 12.14 MPa. Benefiting from the crosslinked structure and high proton conductivity, the accordingly formed membrane electrode assembly possesses a high open circuit voltage of 1.01 V and the improved Ohmic polarization, delivering a peak power density of 0.66 W cm^-2 using hydrogen as fuel and air as oxidant.

Rational design and precise synthesis of cost-effective and highly-active Pt-alternative anode catalysts are important paths to accelerate the application and promotion of direct methanol fuel cell. Herein, a robust and controllable synthetic strategy is developed to the bottom-up construction of carbon nanotube-bridged Ti₃C₂T_x MXene nanoarchitectures decorated with ultrasmall Rh nanoparticles (Rh/CNT-MX) through a facile co-assembly process. The existence of MXene nanosheets with abundant anchoring sites can immobilize nanosized Rh crystals and facilitate their dispersion, while the integration of CNT skeletons effectively separates the neighboring MXene layers and offers unimpeded electron transport channels, which are conducive to making full use of respective catalytic functions for each component. As a consequence, the optimized Rh/CNT-MX catalyst expresses superior methanol oxidation performance with a considerable electrochemically active surface area of 89.4 m² g^-1, high mass/specific activity of 911.0 mA mg^-1/1.02 mA cm^-2, and reliable long-term durability, which has obvious competitive advantages over the conventional Rh/carbon black, Rh/CNT, Rh/MXene as well as commercial Pt/carbon black and Pd/carbon black catalysts.

With the rapid development of biomedical technology, biodegradable and implantable energy storage devices for biosensor and bioelectronics applications have attracted the great attention of scientists. However, the limited energy density, poor biocompatibility and excessive space occupation of existing biodegradable energy storage devices pose major challenges to their application in the biomedical field. To address these challenges, in this work, flexible Ti₃C₂T_x film with an adhesive-free structure constructed is proposed as electrode material for the flexible solid-state biodegradable supercapacitor (FSBSC). The morphology and structure of MXene films were characterized by XRD, XPS, Raman, SEM and TEM. A 0.9% NaCl saline, similar human body fluids was used as the electrolyte solution to construct symmetrical FSBSC (Ti₃C₂T_x//NaCl-PVA//Ti₃C₂T_x-FSBSC). The Ti₃C₂T_x//NaCl-PVA//Ti₃C₂T_x-FSBSC exhibits a high capacitance of 112 F/g at 1 A/g, excellent rate capability (73.2% at 20 A/g), long lifetime (81.6 % after 10,000 cycles), and high specific energy/power (62.3 Wh/kg at 1,000.8 W/kg). The charge storage mechanism was analyzed using ex-situ XRD, XPS and density function theory (DFT). DFT results show that the Ti₃C₂T_x (T_x = O)) electrode possesses metallic properties. The calculated adsorption energies (E_ads) and smaller diffusion barriers of Na⁺-ions further proved the outstanding performance of the Ti₃C₂T_x electrode. Moreover, the apparatus is entirely biodegradable, thereby paving a promising path for the progression of bioelectronics and biomedical energy storage technologies.

As one of the most promising energy storage devices, Lithium-sulfur batteries (LSBs or Li-S batteries) are still facing obstacles due to the notorious shuttling of soluble polysulfide intermediates, accompanied by low S utilization, corrosion of the lithium anode, and rapid capacity fading leading to a short cycling life. To overcome these issues and achieve high-performance LSBs, we introduce a modified separator composed of multi-walled carbon nanotubes/lithium lanthanum titanium oxide (MWCNTs/LLTO). The proposed MWCNTs/LLTO-modified separator improves the redox reaction kinetics from soluble higher-order lithium polysulfides to the insoluble lower-order ones and ultimately to Li₂S, thereby reducing the polysulfides dissolved in the electrolyte. It also serves as a physical barrier to adsorb polysulfides, efficiently preventing their diffusion from the cathode to the anode. LSBs adopting the MWCNTs/LLTO-modified separator exhibit higher ionic and electronic conductivity than the un-modified counterparts, leading to an initial specific capacity of 1496 mA h g⁻¹ (∼90% of the theoretical capacity) at 0.1C, an excellent rate capability performance, and a remarkable capacity retention of 80% after 200 cycles. Furthermore, the cells with S loading reaching up to 4.18 mg cm^-2 further confirmed the beneficial impact of the MWCNTs/LLTO-modified separator.

The replacement of sluggish oxygen evolution reaction by more thermodynamically favorable ethanol oxidation reaction (EOR) is a promising strategy for co-production of hydrogen and valuable chemicals in energy-saving mode. Here, we propose the synthesis of highly curved PdOs bimetallene, which possesses high active sites atomic utilization and conductivity. Furthermore, alloy effect can regulate electronic structure and optimize adsorption energy of reactants. Therefore, PdOs bimetallene exhibits superior performance for hydrogen evolution reaction (HER) and EOR under basic solutions, with overpotential of 36 mV at 10 mA cm^-2 and mass activity of 1.51 mA μg^-1_Pd, respectively. In the EOR-HER co-electrolysis system, PdOs bimetallene requires low voltage of 0.801 V for concurrent production of hydrogen and acetate at 50 mA cm⁻², which greatly reduces energy consumption compared to conventional water electrolysis (1.976 V). This method provides a promising strategy for designing bimetallic electrocatalysts towards simultaneous energy-saving generation of hydrogen and high-value chemicals by replacing sluggish OER with more favorable ethanol oxidation reaction.