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Chemical manipulation of surface functional groups on two‐dimensional transition metal carbides and/or nitrides (MXenes) provides a wide range of design and application prospects. However, achieving rapid targeted modification of surface groups remains a significant challenge. Herein, we propose a general strategy to swiftly shear and customize surface groups on Ti3C2Tx−MXene via the flash Joule heating (FJH) reaction within 1 s. Successfully, MXenes with 9 target terminations, including VII A (F, Cl, Br, or I), VI A (O, S, or Se), and V A (N or P), either single or multiple, are synthesized, with a surface content of up to about 76 %. The impact of these terminations is systematically analyzed on electrochemical performance, demonstrating that VI A and V A terminations have higher electrochemical activity than VII A. Particularly, N‐, S‐, and O‐terminated MXenes exhibit enhanced specific capacities and undecayed cycling performance. These findings offer valuable insights for the surface engineering design and performance optimization of functional materials. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (AZIBs) have stimulated extensive attention due to their environmental friendliness and low cost. Unfortunately, the inevitable dendrite growth and corrosion on the zinc (Zn) anode severely hinder the practical application of AZIBs. Herein, an amino acid containing an imidazole group is introduced as an effective additive to address these issues. The dynamic conversion of amino acid and protonated amino acid creates a pH buffer function that regulates solution pH in real time, inhibits hydrogen evolution reaction (HER), and eliminates notorious by‐products. In addition, the protonated amino acid is preferentially adsorbed on the Zn anode, preventing contact of the active water with the Zn surface and promoting homogeneous Zn deposition. Thus, the amino acid‐based electrolyte promotes dendrite free plating/stripping with a Coulombic efficiency up to 99.67% and cycle lifetime of 2600 h. In particular, a depth of discharge of up to 87% can be achieved with an ultra‐high areal capacity of 24 mAh cm−2. The developed Zn||CVO full cell also exhibits better electrochemical performance than that without additives. This work provides an effective and convenient approach for safe and efficient Zn‐ion batteries. [ABSTRACT FROM AUTHOR]

The lack of high‐performance electrodes is a key factor restricting the development of sodium‐ion batteries (SIBs), and usually a certain type of electrode material alone often fails to combine the merits of high capacity and good conductivity. Herein, nitrogen‐doped carbon (NC) was used as a multifunctional bridge to uniformly compound high‐capacity MoS2 nanoparticles with highly conductive Ti3C2Tx nanosheets to form Ti3C2Tx@MoS2/NC composite with flower‐like architecture. Ultrafine MoS2 nanoparticles were uniformly anchored on Ti3C2Tx nanosheets to form nanosheets primary building blocks with a sandwich‐like architecture, which not only shortens the ion transfer distance but also enlarges the layer spacing of Ti3C2Tx favoring the storage of more sodium ions as well as their transport capacity. Moreover, the flower‐like structures with abundant edges can provide an ample active sites and high pseudocapacitance behavior. As a result, flower‐like Ti3C2Tx@MoS2/NC displays a high electrochemical properties with an excellent cycling stability over 2000 cycles (81.4 % capacity retention) and preeminent rate capacity of 383 mAh g−1 at 30 A g−1. Furthermore, Ti3C2Tx@MoS2/NC‖Na3V2(PO4)3 full cell displays a capacity of 59 mAh g−1 at 0.4 A g−1 after 180 cycles. This work displays a high‐performance anode composite for SIBs and provides insight into the preparation of other composites. [ABSTRACT FROM AUTHOR]

Aqueous Mg ion batteries (AMIBs) show great potential in energy storage for their advantages of high capacity, abundant resource, and environmental friendliness. However, the development of AMIBs is limited due to the scarcity of suitable anode materials. In this study, a new polymer anode material (PNTAQ) with flower‐like nanosheet structure is synthesized for aqueous Mg‐Na hybrid‐ion battery (AMNHIB). PNTAQ possess carbonyl functional groups which can be oxidized and reduced reversibly in aqueous solution containing alkaline metal ions. PNTAQ displays a discharge specific capacity of 245 mAh g−1 at 50 mA g−1 in 1 M MgCl2 + 0.5 M NaCl electrolyte, which is much higher than that in single 1 M MgCl2 or 0.5 M NaCl electrolyte. Even cycling at 1000 mA g−1 for 1000 times, the capacity retention can still maintain at 87.2%. A full Mg‐Na hybrid‐ion cell is assembled by employing β‐MnO2 as cathode and PNTAQ as anode material, it exhibits a specific capacity of 91.6 mAh g−1 at 100 mA g−1. The polymer electrode material well maintains its framework structure during the discharge/charge cycling process of the hybrid‐ion battery. [ABSTRACT FROM AUTHOR]

Aqueous Mg‐ion batteries (MIBs) lack reliable anode materials. This study concerns the design and synthesis of a new anode material – a π‐conjugate of 3D‐poly(3,4,9,10‐perylenetracarboxylic diimide‐1,3,5‐triazine‐2,4,6‐triamine) [3D‐P(PDI‐T)] – for aqueous MIBs. The increased aromatic structure inhibits solubility in aqueous electrolytes, enhancing its structural stability. The 3D‐P(PDI‐T) anode exhibits several notable characteristics, including an extremely high rate capacity of 358 mAh g−1 at 0.05 A g−1, A 3D‐P(PDI‐T)‖Mg2MnO4 full cell exhibits a reversible capacity of 148 mAh g−1 and a long cycle life of 5000 cycles at 0.5 A g−1. The charge storage mechanism reveals a synergistic interaction of Mg2+ and H+ cations with C−N/C=O groups. The assembled 3D‐P(PDI‐T)‖Mg2MnO4 full cell exhibits a capacity retention of around 95 % after 5000 cycles at 0.5 A g−1. This 3D‐P(PDI‐T) anode sustained its framework structure during the charge–discharge cycling of Mg‐ion batteries. The reported results provide a strong basis for a cutting‐edge molecular engineering technique to afford improved organic materials that facilitate efficient charge‐storage behavior of aqueous Mg‐ion batteries. [ABSTRACT FROM AUTHOR]

Sodium‐ion hybrid capacitors (SIHCs) are considered a prospective alternative to lithium‐ion batteries (LIBs) since there are rich and available sodium reserves. Here, nitrogen‐doped carbon tubes (N‐MJ) derived from metaplexis japonica fluff are prepared by using a facile method of etching and peeling the fluff with urea to prepare a Na+ storage anode. With prominent traits in terms of structure and a high nitrogen content (11.08 %), N‐MJ exhibits exceptional Na+ storage performance with a high reversible capacity (390.9 mAh g−1 at 50 mA g−1) and excellent long‐term circulation (208.1 mAh g−1 after 2650 cycles at 1 A g−1). Systemic kinetic analysis manifests that the extraordinary performance is responsible for the large‐scale capacitance control. Furthermore, the SIHCs assembled by using N‐MJ and activated carbon (AC) presents a maximum energy density of 111.4 Wh kg−1 (at 445.8 W kg−1) and power density of 2455.2 W kg−1 (at 34.1 Wh kg−1). Notably, the developed SIHCs maintain a 100 % capacity retention rate at 1 A g−1 after 5000 cycles. Overall, our work not only provides a good choice for storage Na+ anode materials, but also supplies a feasible method for the recycling of waste biomass. [ABSTRACT FROM AUTHOR]

Potassium‐ion hybrid capacitors have attracted increasing attention due to good energy density, high power density, and low cost. Ti3C2Tx‐MXene is considered as a promising anode material for K ion storage. However, undesirable stacking issues decrease its exposed area and breeds sluggish K ion transport. Herein, a facile spray‐lyophilization strategy is proposed to construct stacking‐resistant Ti3C2Tx with 3D structures. As‐prepared Ti3C2Tx hollow spheres/tubes present stack resistance, a large specific surface area, and a short ion diffusion pathway. When serving as an anode material, it shows enhanced capacity and thickness‐independent rate performance compared to 2D Ti3C2Tx. After 10 000 cycles, a specific capacity of 122 mAh g−1 is obtained at 1 A g−1. Systematic kinetics analyses demonstrate the significance of concentration polarization on the electrode's rate ability. Furthermore, a 3D Ti3C2Tx‖hierarchical porous activated carbon (HPAC) K‐ion hybrid capacitor is assembled and displays remarkable energy and power densities with energy retention of 100% after 10 000 cycles at 1 A g−1. Following this strategy, other 3D structures from nanosheets can also be obtained, such as 3D Ti3C2Tx microtubes and graphene oxide nanoscrolls. This study provides a viable approach to solve the stacking issues of 2D nanosheets to promote the application of 2D materials. [ABSTRACT FROM AUTHOR]

Aqueous batteries have attracted increasing and extensive attention, owing to their high safety, low cost, and low toxicity. These factors have become increasingly important, given the current focus on the rapid development of green energy technologies. In particular, multivalent‐ion batteries are emerging as alternatives to lithium‐ion batteries. Unfortunately, magnesium and aluminum ions have high polarization strengths that are unfavorable for electrode materials. In contrast, calcium‐ion batteries successfully avoid the problem of high polarization. Herein, an aqueous calcium‐ion battery (CIBs) based on mesoporous silica SBA‐15 with a two‐dimensional hexagonal through‐hole structure is reported. The poly(3,4,9,10‐perylentetracarboxylic diimide) (PPTCDI) organic material supported on SBA‐15 is used as the anode and displays a capacity of 201 mAh g−1, with a stable cycling performance of 95 % capacity retention after 1500 cycles. SBA‐15@PPTCDI‖Ca2MnO4 aqueous CIBs demonstrate a high energy density of 130.6 Wh kg−1 in the cell voltage range from 0.0 to 1.8 V, with a high capacity and excellent cycling stability. As the anode material, SBA‐15@PPTCDI shows special bonding of redox electrons that leads to its highly stable performance, which paves the way for addressing the shortcomings of traditional organic electrode materials. The localization and delocalization of the redox electron offers additional voltage stability, which is another important advantage for practical applications. This study highlights the potential of organic electrode materials for applications in aqueous multivalent‐metal‐ion batteries. [ABSTRACT FROM AUTHOR]

A fast one‐step arc discharge exfoliation method is employed to synthesize Si/graphene composites by using a graphite rod filled with a mixture of Si powder and urea as a cathode. During the arc discharge process, the use of urea allows both the introduction of nitrogen atoms into the graphene and the uniform sealing of Si nanoparticles between the thin graphene sheets to occur simultaneously. The resulting N‐doped graphene nanosheets embedded with Si (Si@NG) can act as an electrode material for lithium‐ion batteries and delivers the reversible capacity of 1030 mAh g−1 with a current density of 200 mA g−1 over 100 cycles along with an outstanding coulombic efficiency of 96.84 %. The remarkable electrochemical rate capability performance can be owed to the multiple role of NG, which not only serves as a three‐dimensional conductive support, but also effectively limits the volume variation of Si nanoparticles. The approach proposed here is expected to be extended to the preparation of other alloy anode/graphene hybrids for lithium ion batteries. [ABSTRACT FROM AUTHOR]