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HighlightsA freestanding MXene-derived defect-rich TiO2@reduced graphene oxides (M-TiO2@rGO) foam electrode was fabricated.M-TiO2@rGO presents fast Na+ storage kinetics due to capacitive contribution.M-TiO2@rGO foam electrode displays a capacity retention of 90.7% after 5000 cycles.Sodium ion batteries and capacitors have demonstrated their potential applications for next-generation low-cost energy storage devices. These devices's rate ability is determined by the fast sodium ion storage behavior in electrode materials. Herein, a defective TiO2@reduced graphene oxide (M-TiO2@rGO) self-supporting foam electrode is constructed via a facile MXene decomposition and graphene oxide self-assembling process. The employment of the MXene parent phase exhibits distinctive advantages, enabling defect engineering, nanoengineering, and fluorine-doped metal oxides. As a result, the M-TiO2@rGO electrode shows a pseudocapacitance-dominated hybrid sodium storage mechanism. The pseudocapacitance-dominated process leads to high capacity, remarkable rate ability, and superior cycling performance. Significantly, an M-TiO2@rGO//Na3V2(PO4)3 sodium full cell and an M-TiO2@rGO//HPAC sodium ion capacitor are fabricated to demonstrate the promising application of M-TiO2@rGO. The sodium ion battery presents a capacity of 177.1 mAh g−1 at 500 mA g−1 and capacity retention of 74% after 200 cycles. The sodium ion capacitor delivers a maximum energy density of 101.2 Wh kg−1 and a maximum power density of 10,103.7 W kg−1. At 1.0 A g−1, it displays an energy retention of 84.7% after 10,000 cycles.

Highlights Nitrogen and phosphorus dual-doped multilayer graphene (NPG) was prepared by arc discharge process. NPG exhibits good rate capability and stable cycling performance in both lithium and potassium ion batteries. Full carbon-based lithium/potassium ion capacitors are assembled and show excellent electrochemical performance. Lithium/potassium ion capacitors (LICs/PICs) have been proposed to bridge the performance gap between high-energy batteries and high-power capacitors. However, their development is hindered by the choice, electrochemical performance, and preparation technique of the battery-type anode materials. Herein, a nitrogen and phosphorus dual-doped multilayer graphene (NPG) material is designed and synthesized through an arc discharge process, using low-cost graphite and solid nitrogen and phosphorus sources. When employed as the anode material, NPG exhibits high capacity, remarkable rate capability, and stable cycling performance in both lithium and potassium ion batteries. This excellent electrochemical performance is ascribed to the synergistic effect of nitrogen and phosphorus doping, which enhances the electrochemical conductivity, provides a higher number of ion storage sites, and leads to increased interlayer spacing. Full carbon-based NPG‖LiPF 6 ‖active carbon (AC) LICs and NPG‖KPF 6 ‖AC PICs are assembled and show excellent electrochemical performance, with competitive energy and power densities. This work provides a route for the large-scale production of dual-doped graphene as a universal anode material for high-performance alkali ion batteries and capacitors.

Graphite is the state‐of‐the‐art anode material for most commercial lithium‐ion batteries. Currently, graphite in the spent batteries is generally directly burned, which caused not only CO2 emission but also a waste of precious carbon resources. In this study, we regenerate graphite in lithium‐ion batteries at the end of life with excellent electrochemical properties using the fast, efficient, and green Flash Joule Heating method (FJH). Through our own developed equipment, under constant pressure and air atmosphere, graphite is rapidly regenerated in 0.1 s without pollutants emission. We perform a detailed analysis of graphite material before and after recovery by multiple means of characterization and find that the regenerated graphite displays electrochemical properties nearly the same as new graphite. FJH provides a large current for defect repair and crystal structure reconstruction in graphite, as well as allowing the SEI coating to be removed during ultra‐fast annealing. The electric field guide the conductive agent and binder pyrolysis products to form conductive sheet graphene and curly graphene covering the graphite surface, making the recycled graphite even better than new commercial graphite in terms of electrical conductivity. Regenerated graphite has excellent multiplier performance and cycle performance (350 mAh g−1 at 1 C with a capacity retention of 99% after 500 cycles). At cost, we get recycled graphite that displays the same performance as new graphite, costing just 77 CNY per ton. This FJH method is not only universal for the regeneration of spent graphite generated by various devices but also enables multiple use‐failure‐regeneration steps of graphite, showing great potential for commercial applications. The regeneration of the spent graphite can be realized by FJH treatment, and the performance of the regenerate graphite can be comparable to the new commercial graphite, which realizes the rapid and environmental recycling of the spent anode, and greatly reduces the material cost.

Mesoporous ZSM-5 zeolite (MZ) was used as support for Cu and Ce species, and the effects of structure and physical-chemical properties on selective catalytic reduction of NO with NH 3 (NH 3 -SCR) were investigated. The characterization and experimental results show that the high activity of the Cu-Ce/MZ catalyst could be due to its high surface area, more and uniformly distributed active sites, and abundant oxidative species. Compared with the conventional ZSM-5 and SBA-15, the Cu-Ce/MZ possesses large amount of mesopores, and more accessible active sites, which are beneficial to accelerate the diffusion and improve the internal mass transfer in the denitration process. The Cu-Ce/MZ catalyst shows higher activity than Cu-Ce/ZSM-5 and Cu-Ce/SBA-15 at 200 °C.

Aqueous zinc (Zn)-based energy storage devices possess promising applications for large-scale energy storage systems due to the advantage of high safety, low price, and environment-friendliness. However, their development is restricted by dendrite growth and hydrogen evolution issues from the Zn-metal anode. Herein, a facile stress-pressing method is reported for constructing a grid zinc anode (GZn) with a conductive framework. The highly conductive copper (Cu)-mesh framework reduces electrode hydrogen evolution and increases electrode conductivity. Meanwhile, the in situ-formed Cu-Zn nano-alloy stabilizes the Zn deposition interface. As a result, the GZn symmetrical cell presents a low overpotential of 49 mV after cycling for 1,200 h (0.2 mA∙cm −2 ). In addition, GZn displays its potential application as a universal anode for Zn-ion capacitors and batteries. An activated carbon||GZn Zn-ion capacitor delivers a stable cycling performance after 10,000 cycles at 5 A∙g −1 and MnO 2 ||GZn Zn-ion batteries exhibit satisfactory cycle stability and excellent rate performance. This demonstrates that GZn appears to be a promising universal anode for Zn-ion capacitors and batteries.

Metal sulfides have shown great potential as the anodes of the asymmetric supercapacitors ascribed to their superior theoretical specific capacitance. However, their specific capacitance and rate performances are still far from the expectation due to the intrinsic poor electronic conductivity and sluggish kinetics. Herein, we employ the anion and cation double‐substitution strategy to prepare iron sulfide nanoparticles on graphene composite (denoted as NiFeSP/G) to improve the electronic conductivity of FeS2. The NiFeSP/G composite exhibits greatly improved electrochemical performances with a high specific capacity of 765 C g−1 (765 F g−1) at 5 A g−1 and a remarkable rate capability of 65% at 100 A g−1. Moreover, an aqueous asymmetric supercapacitor is fabricated with the NiFeSP/G as anode and NiCo‐LDH/graphene as cathode presents an impressively high energy density up to 109 Wh kg−1 at 1591 W kg−1 and cycling performance (89% of the initial capacity retained after 8000 cycles). The effective strategy of anion (P) and cation (Ni) double‐substitution along with the incorporation of graphene nanosheets greatly improves the electrochemical performances of iron sulfide. An aqueous asymmetric supercapacitor is fabricated with the NiFeSP/G and NiCo‐LDH/G as the anode and cathode, respectively.

Lithium‐sulfur batteries attract lots of attention due to their high specific capacity, low cost, and environmental friendliness. However, the low sulfur utilization and short cycle life extremely hinder their application. Herein, we design and fabricate a three‐dimensional electrode by a simple filtration method to achieve a high‐sulfur loading. Biomass porous carbon is employed as a current collector, which not only enhances the electronic transport but also effectively limits the volume expansion of the active material. Meanwhile, an optimized carboxymethyl cellulose binder is chosen. The chemical bonding restricts the shuttle effect, leading to improved electrochemical performance. Under the ultrahigh sulfur load of 28 mg/cm2, the high capacity of 18 mAh/cm2 is still maintained, and stable cycling performance is obtained. This study demonstrates a viable strategy to develop promising lithium‐sulfur batteries with a three‐dimensional electrode, which promotes sulfur loading and electrochemical performance. Carbonized biomass has a unique array‐like straight tube structure that effectively limits the volume expansion of sulfur during discharge. The slurry formed by mixing the aqueous binder and S is drawn into the self‐supporting carbon sheet by a vacuum suction method. This design can greatly improve the capacity and cycle performance of the electrode at high S loading.

NiMoO 4 has attracted intensive attention as one of the promising ternary metal oxides because of its high specific capacitance and electrical conductivity compared to traditional transition-metal oxides. In this study, NiMoO 4 nanorods uniformly decorated on graphene nanosheets (G-NiMoO 4 ) are synthesized through a facile hydrothermal method. The prepared G-NiMoO 4 composite exhibits a high specific capacitance of 714 C·g −1 at 1 A·g−1 and an excellent rate capability, with a retention ratio of 57.7% even at 100 A·g −1 . An asymmetric supercapacitor (ASC) fabricated with the G-NiMoO 4 composite as the positive electrode and Fe 2 O 3 quantum dot-decorated graphene (G-Fe 2 O 3 -QDs) as the negative electrode delivers an ultrahigh energy density of 130 Wh·kg −1 , which is comparable to those of previously reported aqueous NiMoO 4 -based ASCs. Even when the power density reaches 33.6 kW·kg −1 , an energy density of 56 Wh·kg −1 can be maintained. The ASC device exhibits outstanding cycling stability, with a capacitance retention of 113% after 40,000 cycles. These results indicate that the G-NiMoO 4 composite is a promising candidate for ASCs with ultrahigh energy density and excellent cycling stability. Moreover, the present work provides an exciting guideline for the future design of high-performance supercapacitors for industrial and consumer applications via the simultaneous use of various pseudocapacitive materials with suitable potential windows as the positive and negative electrodes.

In order to alleviate the energy crisis and propel a low-carbon economy, hydrogen (H2) plays an important role as a renewable cleaning resource. To break the hydrogen evolution reaction (HER) bottleneck, we need high-efficiency electrocatalysts. Based on the synergistic effect between bimetallic oxides, hierarchical mesoporous CoNiO2 nanosheets can be fabricated. Combining physical representations with electrochemical measurements, the resultant CoNiO2 catalysts present the hierarchical microflowers morphology assembled by mesoporous nanosheets. The ultrathin two-dimensional nanosheets and porous surface characteristics provide the vast channels for electrolyte injection, thus endowing CoNiO2 the outstanding HER performance. The excellent performance with a fewer onset potential of 94 mV, a smaller overpotential at 10 mA cm−2, a lower Tafel slope of 109 mV dec−1 and better stability after 1000 cycles makes CoNiO2 better than that of metallic Co and metallic Ni.

Sodium-ion batteries (SIBs) have garnered significant interest in energy storage due to their similar working mechanism to lithium ion batteries and abundant reserves of sodium resource. Exploring facile synthesis of a carbon-based anode materials with capable electrochemical performance is key to promoting the practical application of SIBs. In this work, a combination of petroleum pitch and recyclable sodium chloride is selected as the carbon source and template to obtain hard carbon (HC) anode for SIBs. Carbonization times and temperatures are optimized by assessing the sodium ion storage behavior of different HC materials. The optimized HC exhibits a remarkable capacity of over 430 mAh·g –1 after undergoing full activation through 500 cycles at a density of current of 0.1 A·g –1. Furthermore, it demonstrates an initial discharge capacity of 276 mAh·g –1 at a density of current of 0.5 A·g –1. Meanwhile, the optimized HC shows a good capacity retention (170 mAh·g –1 after 750 cycles) and a remarkable rate ability (166 mAh·g –1 at 2 A·g –1). The enhanced capacity is attributed to the suitable degree of graphitization and surface area, which improve the sodium ion transport and storage.