Ultrahigh Loading Research Articles

Anode interface-stabilizing dry process employing a binary binder system for ultra-thick and durable battery electrode fabrication

Polytetrafluoroethylene (PTFE)-based dry process has gained attention in the battery industry owing to their sustainability, cost-effectiveness, and ability to fabricate high loading electrodes. However, the electrochemical instability of PTFE in anodic environments causes significant capacity loss, hindering the development of high-performance dry-processed anodes. In this study, a binary binder system of PTFE and polyvinylpyrrolidone (PVP) is proposed to prevent direct contact between graphite and PTFE, mitigating unwanted interphase evolution. This strategy improves the mechanical integrity of the electrode. It maintains the binding force between the active materials and PTFE binders. PVP also forms a robust inorganic-rich SEI, enhancing Li-ion kinetics and interfacial stability. Consequently, dry-processed graphite with PVP achieved ultra-high loading anodes (∼10 mAh cm−2) with excellent cycle stability over 200 cycles in full cells coupled with LiNi0.8Co0.1Mn0.1O2 cathodes. This paper presents a cost-effective, high-loading electrode fabrication process and an eco-friendly approach for large-scale electrification.

Sintering of c-BC<sub>2</sub>N particles, solid solutions of metallic phases with additives of oxide components and NiCr at ultrahigh load and temperature of plasma spark sintering, high compression pressure during the explosive method

Sintering of c-BC<sub>2</sub>N particles, solid solutions of metallic phases with additives of oxide components and NiCr at ultrahigh load and temperature of plasma spark sintering, high compression pressure during the explosive method

Engineering Nano-Pills to Inhibit Ovarian Cancer Proliferation and Migration through a Combination of Chemical/Nucleic Acid Therapy.

Ovarian cancer (OC) is the most fatal of all gynecological malignancies, presenting a significant threat to women's health. Its treatment is complicated by severe dose-dependent chemotherapy toxicity, drug resistance, and tumor migration. Herein, an intelligent combination strategy of chemotherapy and nucleic acid therapy, named ApMEmiR&D is developed. This integrated system consists of three parts: the nano-pill, the protective membrane, and the navigation element. Nano-pills are nanospheres assembled from miRNA and doxorubicin (DOX) with the help of ferrous ions (Fe2+). The protective membrane is derived from tumor-associated macrophages (TAMs membrane) originating from the primary tumor microenvironment (TME). The navigation element is the cholesterol-conjugated AS1411 aptamer. The resulting ApMEmiR&D nanoparticles exhibit uniform size, a well-defined nanosphere structure, robust serum stability, and ultra-high drug loading efficiency and capacity. The system can efficiently accumulate in the tumor, allowing for the synergistic inhibition of tumor growth and metastasis without apparent systemic toxicity. The results demonstrate the homing effect of tumor microenvironment-derived macrophage cell membrane and the targeting effect of aptamer, leading to precise drug targeting and immune compatibility, thereby enhancing therapeutic efficacy. The success of this strategy paves the way for metastasis inhibition and targeted cancer therapy.

Edge Electron Effect Induced High-Entropy SEI for Durable Anode-Free Sodium Batteries.

Anode-free sodium metal batteries represent great promising as high-energy-density and resource-rich electrochemical energy storage systems. However, the savage growth of sodium metal and continuous consumption hinder its stable capacity output. Herein, ordered flower-edges of zinc on Al substrate can induce high-entropy solid electrolyte interphase (SEI) to adjust sodium uniform deposition and extremely reduce electrolyte consumption with ultrahigh initial Coulombic efficiency (97.05%) for prolong batteries cycling life. Theoretical and experimental studies have demonstrated that the electron-donating property and exposed edge sites between (100) and (101) facets in zinc flower enhance anion adsorption onto the inner Helmholtz plane accelerating its interface decomposition. Additionally, the ordered zinc edges serve as homogeneous-nucleating template, leading to thin and inorganic-rich SEI layer (18 nm, ZnF2, NaZn13, NaF, and Na2CO3) with high-entropy discrete multicomponent distribution, so that fast and high-flux Na ions transport field, thereby reducing the critical nucleation barrier and promoting sodium high density nucleation (7.36 × 1013 N cm-2) and pyknotic growth (3 mAh cm-2, 22µm). The assembled anode-free sodium batteries exhibit high stability (86%, 90 cycles) under ultrahigh cathode loading (32 mg cm-2). Moreover, the anode-less single-layer pouch batteries exhibit a durable capacity retention of 99% after 600 cycles.

Boosting Li-S batteries through the synergistic effect of recycled ferrites and external magnetic induction

Despite being considered one of the most promising energy storage technologies, lithium-sulfur batteries (LSBs) are limited in terms of commercialization by the shuttle effect and slow reaction kinetics. In this work, we demonstrate for the first time that the use of recycled ferrite in conjunction with an external magnetic field generated by a permanent magnet can enhance the reaction kinetics and the adsorption of polysulfides (LiPSs), and hence the electrochemical stability. An in-depth kinetic study shows that under the effect of an external magnetic field, the electrode has lower polarization, a higher Li+ diffusion coefficient and a lower activation energy between electrochemical stages. The electrode also has a capacity retention up to 40 % higher and half the capacity loss per cycle at a high rate of 1C. At an ultra-high rate of 10C, the electrode has a capacity of 507 mAh g−1 after 150 cycles and an areal capacity of up to 3 mAh cm−2 at an ultra-high loading of 13 mg cm−2. In addition to the promising results observed in electrochemical terms, our approach is also more sustainable due to the use of a recycled electronic material obtained via dry milling, thereby avoiding the use of fossil carbons.

Ultra-high Prussian blue loading in SPEEK matrix fabricated by one-step electrostatic spraying as proton exchange membranes for fuel cell

Mixed matrix proton exchange membrane is promising for fuel cell application, but maximizing nanofiller loading to enhance performance is significant challenge. This study developed a one-step electrostatic spraying strategy to prepare ultra-high Prussian blue loading (up to 66.7 wt%) in sulfonated poly(ether ether ketone) matrix (PB@SPEEK). By coupling the electrostatic spraying and in situ solvent evaporation densification, SPEEK fills the voids between PB nanoparticles, forming a bicontinuous microstructure in the membrane. The ultra-high PB content of 66.7 wt% enable a fully utilization of its intrinsic properties, resulting in extremely low swelling ratio of 3.4% at 80°C, excellent flexibility of freely folding, and nearly 100% mass retention after 12-hour immersion in Fenton reagent at 60°C. In single-cell tests, the PB@SPEEK mixed matrix membrane shows stable internal resistance due to easily water hydration, therefore achieving excellent low-temperature peak power (1973.9 mW/cm2 at 40 °C and 2078.0 mW/cm2 at 60°C). The strategy developed in this study enables the one-step preparation of large-area, ultra-thin and ultra-high capacity of inorganic nanofiller mixed matrix proton exchange membranes for high-performance fuel cell.

Li+ Ion-Dipole Interaction-Enabled a Dynamic Supramolecular Elastomer Interface Layer for Dendrite-Free Lithium Metal Anodes.

The unstable lithium (Li)/electrolyte interface, causing inferior cycling efficiency and unrestrained dendrite growth, has severely hampered the practical deployment of Li metal batteries (LMBs), particularly in carbonate electrolytes. Herein, we present a robust approach capitalizing on a dynamic supramolecular elastomer (DSE) interface layer, which is capable of being reduced with Li metal to spontaneously form strong Li+ ion-dipole interaction, thereby enhancing interfacial stability in carbonate electrolytes. The soft phase in the DSE structure enables fast Li+ transport via loosely coordinated Li+-O interaction, while the hard phase, rich in electronegative lithiophilic sites, drives the generation of fast-ion-conducting solid electrolyte interface components, including Li3N and Li2S. Furthermore, the dynamically resilient DSE network composed of soft and hard phases protects Li anodes from electrolyte corrosion and accommodates volume changes during cycling. All features of the DSE layer synergistically facilitate uniform Li+ deposition and suppress Li dendrite propagation, ensuring a stable and dendrite-free Li anode. Consequently, the symmetric Li||Li cell incorporating the DSE layer achieves cycling stability exceeding 6000 h under 1 mA cm-2 and 1 mA h cm-2 conditions. Furthermore, full cell pairing DSE/Li anode with LiFePO4 (LFP) or high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes exhibits high-efficiency Li deposition and cycling stability, even under constrained conditions of limited Li (40 μm) and ultrahigh loading NMC811 cathode (21.5 mg cm-2). This study underscores the effectiveness of the ion-dipole interaction-enabled DSE network in developing stable, high-energy-density LMBs.

In Situ Constructing Robust Interface by Deep Eutectic Polymeric Electrolyte Enables High Performance Lithium Metal Batteries with High-Loading Cathode.

The low Li+ transport and poor interface have consistently been two major impediments to practical applications of Polyacrylonitrile (PAN)-based composite solid-state electrolytes (PCPE). In this work, a polymerizable deep eutectic electrolyte is meticulously designed with high fluidity which consists of Poly (Ethylene Glycol) Diacrylate (PEGDA), Fluoroethylene Carbonate (FEC), Succinonitrile (SN) and dual salts (LiTFSI/LiDFOB) to promote Li+ transport and ameliorate the interface of PCPE. Inclusion of PEGDA monomers and FEC alters the crystallinity of SN, enhancing the wettability of thick electrode, and formation of polymeric 3D network from polymerization of PEGDA can anchor SN and suppress the side reactions between SN and lithium metal. Consequently, the modified PCPE exhibit an enhanced conductivity of 4.47×10-4Scm-1 with Li-ion transference number of 0.60, and show an excellent lithium stability. LiCoO2(LCO)/SP-PCPE/Li batteries with higher loading (3-4.4V, 6mgcm-2) can work for over 300 cycles at 0.5 C. Even with an ultra-high loading of 16mgcm-2, LCO/SP-PCPE/Li batteries achieve an excellent cycling performance. This work provides new insights into how to construct a robust interface for solid-state batteries with high-loading cathode.

Hierarchical porous MnO2/3D graphene oxide/carbon cloth used as practical mass-loading supercapacitor electrodes

Supercapacitor electrodes with high mass loading of active materials often exhibit low areal capacitances due to stacking problem of heavy loading. In this study, we present a 3D hierarchical porous graphene oxide (GO) nanosheets grown on carbon cloth (CC), termed as 3DGO/CC. With its high specific surface area, ample space to accommodate the volume expansion, and ideal ion transfer pathways, 3DGO/CC emerges as a promising candidate for high-loading active materials. Utilized as an efficient support matrix for MnO2 loading, an ultrahigh mass loading of MnO2 (17.32 mg cm−2) is deposited onto the surface of 3DGO, forming a MnO2/3DGO/CC electrode without stacking. The conductive porous 3DGO/CC composite scaffold optimizes the utilization of MnO2 active material, resulting in a high areal capacitance. An optimal electrode achieves an impressive areal capacitance of 3.18 F cm−2 at 1 mA cm−2 which was 4.1 times higher than that of the pristine MnO2/CC electrode and maintains a retention of 74.5 % at 32-fold current density. Ultimately, the assembled asymmetric supercapacitor demonstrates a superior electrochemical performance with a maximum energy density of 495.36 μWh cm−2 at the power density of 1.02 mW cm−2. This study supplies an efficient method for preparing MnO2-based electrodes with excellent areal capacitance.

Quantitative pre-lithiation modulation of aluminum foil anode kinetics enables high rate and stable cycling of high-loading all-solid-state batteries

Aluminum (Al) foil holds great promise as a pure alloy anode for all-solid-state batteries (ASSBs) due to its suitable potential, high theoretical capacity, and excellent electronic conductivity. However, it remains challenging to achieve high reversibility and stability of the Al foil anode for ASSBs. Herein, we investigate the morphological and lithium (Li) kinetics evolutions of the Al foil anode paired with sulfide solid-state electrolyte (SSE). We identify that the significant reversible capacity loss stems from diminished Li kinetics at low Li contents (LixAl, 0 < x < 0.5), where the accumulation of pores and pure delithiated Al phase obstructs Li diffusion, increasing interfacial resistance and overpotential. Conversely, the Al foil anode with high Li contents (LixAl, 0.5 < x < 1) demonstrates reversible structures and rapid Li kinetics. Through precise pre-lithiation control, ASSBs with LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes exhibit outstanding rate capabilities and cycling stability, achieving over 4,000 cycles with 82.1 % capacity retention at 5C and demonstrating long-term cycling over 1,000 cycles with nearly 100 % capacity retention at ultra-high loadings. This work offers a viable strategy for advancing practical-level ASSBs with enhanced performance and longevity, contributing valuable insights to future battery technology.

An Oriented Diffusion Strategy to Configure All-Region Ultrahigh-Density Metal Single Atoms for High-Capacity Sodium Storage.

Single-atom metals (SAMs), despite being promising for high-utilization catalysis, biomedicine, and energy storage, usually suffer from limited catalytic performance caused by low metal loading. Herein, via an oriented diffusion strategy, all-region ultrahigh-loading (18.9wt.%) Sn-SAMs over carbon nanorings matrix (Sn-SAMs@CNR) are initially achieved based on the transformation of a g-C3N4@SnO2@polydopamine ring-like nested structure. The formation process of Sn-SAMs involves a critical conversion from oxygen-coordination (SnO2) to nitrogen-coordination (Sn-N4) and simultaneous anti-Osterwalder ripening promoted under spatial confinement. Notably, the g-C3N4-derived N-containing gaseous intermediates dynamically drive the oriented diffusion (inside-out diffusion) of Sn-SAMs across the carbon nanorings, realizing an all-region ultrahigh loading of SAMs throughout the carbon matrix. This strategy is also applied to other metal materials (Fe, Co, Ni, Cu, and Sb), and features excellent universality. When applied as the anode for sodium-ion batteries, experimental analyses and theoretical calculations demonstrate that high-loading Sn-N4 active sites significantly optimize electron density distribution and improve reaction kinetics. Consequently, Sn-SAMs@CNR exhibits outstanding durability of 364mAhg-1 even after 5000 cycles with an impressively low (0.00068%) capacity decay per cycle. This work opens up a universally new avenue for all-region ultrahigh loading of SAMs to carbon matrix for high-performance energy storage.

Ultrahigh Single Au Atoms Loaded Porous Aromatic Frameworks for Enhanced Photocatalytic Hydrogen Evolution.

Supported single-atom catalysts (SACs) are promising in heterogeneous catalysis because of their atom economy, unusual transformations, and mechanistic clarity. The metal SAs loading, however, limits the catalytic efficiency. Herein, an in situ pre-metallated monomer-based preparation strategy is shown to achieve ultrahigh Au SAs loading in catalyst formations. The polymerization of single-atom loaded monomers yield a new porous aromatic framework (PAF-164) with Au SAs loading up to a record high 45.3 wt.%. SACs of Au-PAFs exhibit excellent photocatalytic activity in hydrogen (H2) evolution, and the H2 evolution rate of Au100%-SAs-PAF-164 can reach 4.82mmol g-1 h-1 with great recyclability.

Hydrogen susceptibility of Al 5083 under ultra-high strain rate ballistic loading

Abstract The effect of hydrogen on the ballistic performance of aluminum (Al) 5083H131 was examined both experimentally and numerically in this study. Ballistics tests were conducted at a 30° obliquity in accordance with the ballistic test standard MIL-DTL-46027 K. The strike velocities of projectiles were ranged from 240 m s−1 to 500 m s−1 level in the room temperature. Electrochemical hydrogen charging method was utilized to introduce hydrogen into material. Chemical composition of material was analyzed using energy dispersive X-ray (EDX) analysis. Instant camera pictures were captured using high-speed camera to compare H-uncharged and H-charged specimen ballistics tests. The volume loss in partially penetrated specimens were assessed using the 3D laser scanning method. Microstructural examinations were conducted utilizing scanning electron microscopy (SEM). It was observed that with the increased deformation rate, the dominance of the HEDE mechanism over HELP became evident. Furthermore, the experimental findings were corroborated through numerical methods employing finite element analysis (FEM) along with the Johnson–Cook plasticity model and failure criteria. Inverse optimization technique was employed to implement and fine-tune the Johnson–Cook parameters for H-charged conditions. Upon comparing the experimental and numerical outcomes, a high degree of consistency was observed, indicating the effective performance of the model.

Tumor Microenvironment-Responsive Biodegradable Nanomedicine for Self-Enhanced Synergistic Chemo-, Photothermal, and Chemodynamic Therapy.

The nanoscale multidrug codelivery system for synergistic therapy is an effective strategy for tumor treatment. However, the low drug delivery efficiency and poor therapeutic effects limit its application. Here, based on the coordination effect of Artemisinin (Art), quercetin (Qc), and Fe3+, we had constructed a safe and efficient carrier-free hyaluronic acid (HA)-modified Art-Fe-Qc nanoparticles (AFQ@HA NPs) for enhanced chemotherapy/photothermal therapy (PTT)-chemodynamic therapy (CDT) synergistic therapy, which achieved an ultrahigh drug loading efficiency and a multifunction anticancer strategy. The results showed that high drug loading was achieved based on drug coordination self-assembly, with Art and Qc contents of 38.6 and 42.7%, respectively. At the same time, based on the Qc-Fe coordination molecular network, the system had excellent photothermal conversion performance with an efficiency of 57.3% and could effectively inhibit the expression of HSP70, achieving enhanced PTT. Further, under the stimulation of excessive H2O2 and glutathione (GSH) in the tumor microenvironment, the AFQ@HA NPs were continuously degraded, while releasing Art and Fe3+/Fe2+ to achieve iron ion-enhanced CDT. The results of in vitro and in vivo experiments showed that AFQ@HA NPs could achieve chemotherapy-PTT-CDT synergistic therapy in response to tumor microenvironment by passively targeting and actively targeting tumor cells with CD44, demonstrating its excellent targeted antitumor effects.

Hierarchically Porous Structured Adsorbents with Ultrahigh Metal-Organic Framework Loading for CO2 Capture.

Metal-organic frameworks (MOFs) have emerged as promising candidates for CO2 adsorption due to their ultrahigh-specific surface area and highly tunable pore-surface properties. However, their large-scale application is hindered by processing issues associated with their microcrystalline powder nature, such as dustiness, pressure drop, and poor mass transfer within packed beds. To address these challenges, shaping/structuring micron-sized polycrystalline MOF powders into millimeter-sized structured forms while preserving porosity and functionality represents an effective yet challenging approach. In this study, a facile and versatile strategy was employed to integrate moisture-stable and scalable microcrystalline MOFs (UiO-66 and ZIF-8) into a poly(acrylonitrile) matrix to fabricate readily processable, millimeter-sized hierarchically porous structured adsorbents with ultrahigh MOF loadings (∼90 wt %) for direct industrial carbon capture applications. These structured composite beads retained the physicochemical properties and separation performance of the pristine MOF crystal particles. Structured UiO-66 and ZIF-8 exhibited high specific surface areas of 1130 m2 g-1 and 1431 m2 g-1, respectively. The structured UiO-66 achieved a CO2 adsorption capacity of 2.0 mmol g-1 at 1 bar and a dynamic CO2/N2 selectivity of 17 for a CO2/N2 gas mixture with a 15/85 volume ratio at 25 °C. Furthermore, the structured adsorbents exhibited excellent cyclability in static and dynamic CO2 adsorption studies, making them promising candidates for practical application.

MXene Supported Electrodeposition Engineering of Layer Double Hydroxide for Alkaline Zinc Batteries

AbstractThe main challenges faced by aqueous rechargeable nickel‐zinc batteries are their comparatively low energy density and poor cycling stability, mainly due to the limited capacity and reversibility of existing Ni‐based cathodes. Moreover, the preparation procedures of these cathodes are complex and not easily scalable, which makes them less promising for large‐scale energy storage. Herein, we utilized MXene as a functional additive to effectively improve the electrodeposition preparation of NiCo layered double hydroxides (LDH). Benefiting from the improved interfacial contact between nickel foam (NF) and platting solution and the enhanced ionic conductivity of platting product based on MXene additives, the resulting binder‐free NiCo LDH electrode can achieve ultrahigh areal loading (~65 mg cm−2) with abundant active surface for redox reactions and maintained short transport pathway for ion diffusion and charge transfer. Furthermore, the as‐fabricated alkaline NiCo LDH‐based battery delivers high discharge capacity, up to 20.2 mAh cm−2 (311 mAh g−1), accompanied by remarkable rate performance (9.6 mAh cm−2 or 148 mAh g−1 at 120 mA cm−2). Due to the high structural and chemical stability of MXenes/LDH‐based electrode, excellent cycling life can also be achieved with 88.6 % capacity retention after 10000 cycles. In addition, ultrahigh areal energy density (31.2 mWh cm−2) and gravimetric energy density (465 Wh kg−1) can be simultaneously achieved. This work has inspired the design of advanced cathode materials to develop high‐performance aqueous zinc batteries.

Constructing Electron/Ion Conductive‐Enhanced Ultrahigh Loading LiFePO4 Electrodes Using Polytetrafluoroethylene and Carbon Nanotubes for High‐Performance Batteries

Thick electrodes represent an effective approach for augmenting energy density of batteries. However, their increased thickness invariably leads to longer electron and ion transport distance, limiting the utilization of active material and hindering practical application. Herein, an electron‐conducting‐enhanced and ion‐conducting‐enhanced strategy is presented for fabricating ultrahigh loading electrodes via constructing an interlaced 3D network. Carbon nanotubes (CNTs) serve as extended electron pathways. Different from the polyvinylidene fluoride binder which needs to be dissolved into molecules for preparing electrode, polytetrafluoroethylene (PTFE), however, exists as a separate phase inside the electrode, thus can become the extended pathways for electrolyte elongating due to its strong affinity to organic electrolyte. Note that based on the synergistic effect between CNT and PTFE, the latter can exhibit a form of long‐distance extension fibers rather than agglomeration. Finally, a LiFePO4 electrode with a record‐high loading of 141 mg cm−2 is successfully prepared. This electrode exhibits outstanding area capacity (20.7 mAh cm−2 at 0.2 C) and cycling stability with impressive energy density of 224 Wh kg−1 and 517 Wh L−1 in a full cell (graphite anode). The findings present a novel strategy for achieving high energy density in lithium‐ion batteries using existing material systems.

Vertical-channel hierarchically porous 3D printed electrodes with ultrahigh mass loading and areal energy density for Li-ion batteries

Lithium-ion batteries (LIBs) are renowned for their high energy density, long lifespan, and minimal self-discharge, making them a prominent power supply system. However, the persistent demand for improved energy density coupled with mechanical stability remains a significant challenge, as efforts to enhance electrode thickness or achieve geometric complexity through conventional ink-casting methods have yielded limited results. To tackle this challenge, we applied a three-dimensional (3D) printing technique to swiftly construct 3D thick electrodes with ultrahigh mass loading. Combined with unidirectional ice-templating process, high mass loading electrodes with hierarchically porous structures were successfully fabricated. The mass loading of the 3D electrodes can reach up to 73.83 mg cm−2, significantly enhancing the areal capacity. The low tortuosity and good mechanical resilience of these structures enable fast ion and charge transport, leading to significant improvements in areal energy density without sacrificing the power density. The assembled full cell exhibits an impressive areal capacity of 10.34 mAh cm⁻2 at 0.2 C and an excellent energy density of 18.41 mWh cm−2, surpassing other 3D printed lithium-ion batteries. This approach marks a significant advancement in electrode structural design towards higher areal capacity and energy density, showcasing the intriguing potential of 3D printed batteries for practical applications. Additionally, it also highlights the scalability and design versatility provided by 3D printing technique.

Crystallographically textured zinc nucleation and planar electrodeposition for zinc metal batteries via magnetoelectric and magnetization effects

The premature failure of zinc metal anodes is critically associated with the uncontrollable nucleation and random orientation of hexagonal Zn electrodeposits. Herein, we realize to control the crystallographical texture of zinc crystal nuclei and enable planar electrodeposition by simply applying a magnetic field. We unveil the novel mechanism of magnetoelectric and magnetization effects on the different deposition behavior under magnetic fields. The magnetohydrodynamic effect can flatten the uneven electrode surface during electrodeposition by deflecting the motion of Zn2+ ions. Especially, influences of the Hall effect on electrode polarization and magnetization effect on crystallographical Zn nucleation are first uncovered and validated. We demonstrate the proper use of these magnetic field-related effects is propitious to dense, homogeneous, and highly reversible deposition/dissolution of Zn metal anodes. The cycle lives of Zn anodes are extended 2–4 times at different currents and cycling capacities. Moreover, exceptional reversibility of 99.85 % is achieved. Full cells with a low N/P ratio of 5.4 and ultrahigh cathode mass loading of 19.98 mg cm−2 can release stable capacity up to 3.2 mAh cm−2. Our study provides new paradigms for magnetic field regulation of Zn metal battery electrochemistry, as well as for other external field applications in adjusting battery performance.

Se Vacancy Activated Bi2Se3 Nanodots Encapsulated in Porous Carbon Nanofibers for Aqueous Zinc and Ammonium Ion Batteries

AbstractBismuth‐based materials show great potential in aqueous batteries. But it is difficult to design a bifunctional bismuth‐based material for zinc and ammonium ion batteries (ZIBs and AIBs). Herein, a electrospinning method followed by a selenization strategy is used to design Bi2Se3 nanodots embedded in porous carbon nanofibers. Experimental studies coupled with theoretical calculations prove that the designs of nanodot and Se vacancy improve the transfer and storage of Zn2+ and NH4+. Bi2Se3 nanodots are restricted to porous carbon nanofibers during cyclic test. An insertion‐type mechanism is revealed by ex situ characterizations. As a result, this well‐designed electrode (6 mg cm−2) offers high reversible capacities of 270 mA h g−1 in ZIBs and 192 mA h g−1 in AIBs at 0.05 A g−1 and long‐term cycle life (60% capacity retention at 10 A g−1 after 20 K cycles for ZIBs, 78% capacity retention at 2 A g−1 after 9 K cycles for AIBs). Remarkably, it still displays satisfactory performances even at an ultrahigh mass loading of 18 mg cm−2. Furthermore, Zn2+ and NH4+ full cells offer high reversible capacities of 120 and 90 mA h g−1 at 0.05 A g−1 respectively. This work provides a reference for designing a bifunctional electrode.