mAh Cm-2 Research Articles

Universal electrolyte cooling strategy realizes high reversibility of zinc metal anodes

Low temperature operation is often perceived as detrimental due to sluggish reaction kinetics for energy storage systems. However, our investigation underscores a noticeable enhancement in the zinc (Zn) metal reversibility under such conditions. By delving into thermodynamics and kinetics, we demonstrated an electrolyte cooling (e.g. −20 °C) strategy that mitigates the inherent corrosiveness during transient period but also curtails the interaction of reactive species during the battery operations. As a proof concept in a strong-acid electrolyte, Zn metal manifest a reversibility approaching 99.66 % in challenging SUS substrate and 99.94 % in Cu substrate at low current density (e.g. 0.1 mA cm-2), typically plagued by harsh HER. Building on this, we demonstrated a stable Zn-MnO2 full cell at low temperatures over 500 cycles and achieved a high areal-capacity reaching 4.96 mAh cm-2. Additionally, the electrolyte cooling strategy demonstrates impressive universality, proving effective across a diverse range of electrolytes. This investigation provides pivotal insights into modulating the HER and augmenting Zn reversibility, shedding light for the development of aqueous Zn-based storage systems.

In Situ Polymerization of Ultra-Thin and Defect-Free Polyamide Layer for Effectively Impeding the Polysulfides Shuttle.

Lithium-sulfur (Li-S) batteries present significant potential for next-generation high-energy-density devices. Nevertheless, obstacles such as the polysulfide shuttle and Li-dendrite growth severely impede their commercial production. It is still hard to eliminate gaps between individual particles on separators that serve as potential conduits for polysulfide shuttling. Herein, the synthesis of a nanoscale thickness and defect-free cross-linked polyamide (PA) layer on a polypropylene (PP) separator is presented through in situ polymerization. The PA modification layer can effectively impede the diffusion of polysulfides with a thickness of only 1.5nm, as evidenced by the results of cyclic voltammetry (CV) and time-of-flight (TOF) testing. Therefore, the Li/Li symmetric battery assembled with the functional separator exhibits an overpotential of merely 12mV after 1000 h of cycling under test conditions of 1mA cm-2-1 mAh cm-2. Furthermore, the capacity degradation rate of the Li-S battery is only 0.06% per cycle over 450 cycles at 1 C, while the Li-S pouch cell retains 87.63% of its capacity after 50 cycles. This work will significantly advance the preparation and application of molecules in Li-S batteries, and it will also stimulate further research on defect-free modification of separators.

A High Capacity Gas Diffusion Electrode for Li-O2 Batteries.

The very high theoretical specific energy of the lithium-air (Li-O2) battery (3500Wh kg-1) compared with other batteries makes it potentially attractive, especially for the electrification of flight. While progress has been made in realizing the Li-air battery, several challenges remain. One such challenge is achieving a high capacity to store charge at the positive electrode at practical current densities, without which Li-air batteries will not outperform lithium-ion. The capacity is limited by the mass transport of O2 throughout the porous carbon positive electrode. Here it is shown that by replacing the binder in the electrode by a polymer with the intrinsic ability to transport O2, it is possible to reach capacities as high as 31 mAh cm-2 at 1mA cm-2 in a 300µm thick electrode. This corresponds to a positive electrode energy density of 2650Wh L-1 and specific energy of 1716Wh kg-1, exceeding significantly Li-ion batteries and previously reported Li-O2 cells. Due to the enhanced oxygen diffusion imparted by the gas diffusion polymer, Li2O2 (the product of O2 reduction on discharge) fills a greater volume fraction of the electrode and is more homogeneously distributed.

Sodiophilic Substrate Induces NaF-Rich Solid Electrolyte Interface for Dendrite-Free Sodium Metal Anode.

3D substrate with abundant sodiophilic active sites holds promise for implementing dendrite-free sodium metal anodes and high-performance sodium batteries. However, the heightened electrode/electrolyte side reactions stemming from high specific surface area still hinder electrode structure stability and cycling reversibility, particularly under high current densities. Herein, the solid electrolyte interface (SEI) component is regulated and detrimental side reactions are restrained through the uniform loading of Na-Sn alloy onto a porous 3D nanofiber framework (NaSn-PCNF). The strong interaction between Na-Sn alloy and PF6 - anions facilitates the dissociation of sodium salts and releases more free sodium ions for effective charge transfer. Simultaneously, the modulations of the interfacial electrolyte solvation structure and the construction of a high NaF content SEI layer stabilize the electrode/electrolyte interface. NaSn-PCNF symmetrical battery demonstrates stable cycling for over 600 h with an ultralow overpotential of 24.5mV under harsh condition of 10 mA cm-2 and 10 mAh cm-2. Moreover, the full cells and pouch cells exhibit accelerated reaction kinetics and splendid capacity retention, providing valuable insights into the development of advanced Na substrates for high-energy sodium metal batteries.

Highly Reversible and Dendrite-Free Zinc Anodes Enabled by PEDOT Nanowire Interfacial Layers for Aqueous Zinc-Ion Batteries.

The aqueous zinc-ion batteries (ZIBs) have gained increasing attention because of their high specific capacity, low cost, and good safety. However, side reactions, hydrogen evolution reaction, and uncontrolled zinc dendrites accompanying the Zn metal anodes have impeded the applications of ZIBs in grid-scale energy storage. Herein, the poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires as an interfacial layer on the Zn anode (Zn-PEDOT) are reported to address the above issues. Our experimental results and density functional theory simulation reveal that the interactions between the Zn2+ and S atoms in thiophene rings of PEDOT not only facilitate the desolvation of hydrated Zn2+ but also can regulate the diffusion of Zn2+ along the thiophene molecular chains and induce the dendrite-free deposition of Zn along the (002) surface. Consequently, the Zn||Cu-PEDOT half-cell exhibits highly reversible plating/stripping behavior with an average Coulombic efficiency of 99.7% over 2500 cycles at 1 mA cm-2 and a capacity of 0.5 mAh cm-2. A symmetric Zn-PEDOT cell can steadily operate over 1100 h at 1 mA cm-2 (1 mAh cm-2) and 470 h at 10 mA cm-2 (2 mAh cm-2), outperforming the counterpart bare Zn anodes. Besides, a Zn-PEDOT||V2O5 full cell could deliver a specific capacity of 280 mAh g-1 at 1 A g-1 and exhibits a decent cycling stability, which are much superior to the bare Zn||V2O5 cell. Our results demonstrate that PEDOT nanowires are one of the promising interfacial layers for dendrite-free aqueous ZIBs.

High Areal Capacity Cation and Anionic Redox Solid-State Batteries Enabled by Transition Metal Sulfide Conversion.

Pure sulfur (S8 and Li2S) all solid-state batteries inherently suffer from low electronic conductivities, requiring the use of carbon additives, resulting in decreased active material loading at the expense of increased loading of the passive components. In this work, a transition metal sulfide in combination with lithium disulfide is employed as a dual cation-anion redox conversion composite cathode system. The transition metal sulfide undergoes cation redox, enhancing the electronic conductivity, whereas the lithium disulfide undergoes anion redox, enabling high-voltage redox conducive to achieving high energy densities. Carbon-free cathode composites with active material loadings above 6.0 mg cm-2 attaining areal capacities of ∼4 mAh cm-2 are demonstrated with the possibility to further increase the active mass loading above 10 mg cm-2 achieving cathode areal capacities above 6 mAh cm-2, albeit with less cycle stability. In addition, the effective partial transport and thermal properties of the composites are investigated to better understand FeS:Li2S cathode properties at the composite level. The work introduced here provides an alternative route and blueprint toward designing new dual conversion cathode systems, which can operate without carbon additives enabling higher active material loadings and areal capacities.

A Versatile Redox-Active Electrolyte for Solid Fixation of Polyiodide and Dendrite-Free Operation in Sustainable Aqueous Zinc-Iodine Batteries.

Practical utilization of zinc-iodine (Zn-I2) batteries is hindered by significant challenges, primarily stemming from the polyiodide shuttle effect on the cathode and dendrite growth on the anode. Herein, a feasible redox-active electrolyte has been introduced with tetraethylammonium iodide as an additive that simultaneously addresses the above mentioned challenges via polyiodide solidification on the cathode and the electrostatic shielding effect on the anode. The tetraethylammonium (TEA+) captures water-soluble polyiodide intermediates (I3 -, I5 -), forming a solid complex at the cathode, thereby suppressing capacity loss during charge/discharge. Furthermore, the TEA+ mitigates dendrite growth on the Zn anode via the electrostatic shielding effect, promoting uniform and compact Zn deposition at the anode. Consequently, the Zn||Zn symmetric cell demonstrates superior cycling stability during Zn plating/stripping over 4,200h at 1mA cm-2 and 1 mAh cm-2. The Zn||NiNC full-cell exhibits a stable capacity retention of 98.4% after 20000 cycles (>5 months) with near-unity Coulombic efficiency at 1 A g-1. The study provides novel insights for establishing a new direction for low-cost, sustainable, and long-lifespan Zn-I2 batteries.

Engineering d-p Orbital Hybridization with P, S Co-Coordination Asymmetric Configuration of Single Atoms Toward High-Rate and Long-Cycling Lithium-Sulfur Battery.

Single-atom catalysts (SACs) have been increasingly explored in lithium-sulfur (Li-S) batteries to address the issues of severe polysulfide shuttle effects and sluggish redox kinetics. However, the structure-activity relationship between single-atom coordination structures and the performance of Li-Sbatteries remain unclear. In this study, a P, S co-coordination asymmetric configuration of single atoms is designed to enhance the catalytic activity of Co central atoms and promote d-p orbital hybridization between Co and S atoms, thereby limiting polysulfides and accelerating the bidirectional redox process of sulfur. The well-designed SACs enable Li-S batteries to demonstrate an ultralow capacity fading rate of 0.027% per cycle after 2000 cycles at a high rate of 5 C. Furthermore, they display excellent rate performance with a capacity of 619 mAh g-1 at an ultrahigh rate of 10 C due to the efficient catalysis of CoSA-N3PS. Importantly, the assembled pouch cell still retains a high discharge capacity of 660 mAh g-1 after 100 cycles at 0.2 C and provides a high areal capacity of 4.4 mAh cm-2 even with a high sulfur loading of 6mg cm-2. This work demonstrates that regulating the coordination environment of SACs is of great significance for achieving state-of-the-art Li-S batteries.

N-Doped Ti3C2Tx Interfacial Layer Enabling Uniform Zn Deposition along (002) Plane for Stable Aqueous Zinc-Ion Battery.

Aqueous zinc-ion batteries hold great potentials for large-scale grid energy storage. However, the electrode corrosion, hydrogen evolution, and dendrite growth of Zn anode often lead to cell failure. Herein, N groups in Ti3C2Tx (NMXH) are introduced as interfacial layer through hydrothermal treatment of Ti3C2Tx with urea. The experimental analysis and density functional theory calculation indicate that N groups in Ti3C2Tx can homogenize electric field distribution, promote adsorption of Zn2+ on N groups, and strength interactions between N groups and Zn atoms on (002) plane. Thereby, the use of NMXH interfacial layer can effectively suppress the side reactions and realize uniform Zn deposition along the (002) plane. As a consequence, the NMXH─Zn//Zn cell exhibits an ultralow nucleation overpotential (1mA cm-2, 18.9mV) and can stably operate for 1400h at 1mA cm-2 (1 mAh cm-2) and 110h at 40mA cm-2 (1 mAh cm-2). A full battery with V2O5 nanowires as cathode displays a discharge capacity of 219 mAh g-1 (1.0 A g-1), along with a decent rate capability and cyclability. The significant role of N groups reported in this work offers a promising avenue to improve the cycling stability of Zn anodes of aqueous zinc batteries.

Tailoring Oxygen-Depleted and Unitary Ti3C2Tx Surface Terminals by Molten Salt Electrochemical Etching Enables Dendrite-Free Stable Zn Metal Anode.

Two-dimensional Ti3C2Tx MXene materials, with metal-like conductivities and versatile terminals, have been considered to be promising surface modification materials for Zn-metal-based aqueous batteries (ZABs). However, the oxygen-rich and hybridized terminations caused by conventional methods limit their advantages in inhibiting zinc dendrite growth and reducing corrosion-related side reactions. Herein, -O-depleted, -Cl-terminated Ti3C2Tx was precisely fabricated by the molten salt electrochemical etching of Ti3AlC2, and controlled in situ terminal replacement from -Cl to unitary -S or -Se was achieved. The as-prepared -O-depleted and unitary-terminal Ti3C2Tx as Zn anode coatings provided excellent hydrophobicity and enriched zinc-ionophilic sites, facilitating Zn2+ horizontal transport for homogeneous deposition and effectively suppressing water-induced side reactions. The as-assembled Ti3C2Sx@Zn symmetric cell achieved a cycle life of up to 4200 h at a current density and areal capacity of 2 mA cm-2 and 1 mAh cm-2, respectively, with an impressive cumulative capacity of up to 7.25 Ah cm-2 at 5 mA cm-2//2 mAh cm-2. These findings provide an effective electrochemical strategy for tailoring -O-depleted and unitary Ti3C2Tx surface terminals and advancing the understanding of the role of specific Ti3C2Tx surface chemistry in regulating the plating/stripping behaviors of metal ions.

Minimizing Undesired Side Reactions Induced by Nanoscale Conductive Carbon Enables Stable Cycling of Semi-Solid Li-Ion Full Batteries.

Semi-solid lithium-ion batteries (SSLIBs) based on "slurry-like" electrodes hold great promise to enable low-cost and sustainable energy storage. However, the development of the SSLIBs has long been hindered by the lack of high-performance anodes. Here the origin of low initial Coulombic efficiency (iCE, typically <60%) is elucidated in the graphite-based semi-solid anodes (in the non-flowing mode) and develop rational strategies to minimize the irreversible capacity loss. It is discovered that Ketjen black (KB), a nanoscale conductive additive widely used in SSLIB research, induces severe electrolyte decomposition during battery charge due to its large surface area and abundant surface defects. High iCEs up to 92% are achieved for the semi-solid graphite anodes by replacing KB with other low surface-area, low-defect conductive additives. A semi-solid full battery (LiFePO4 vs graphite, in the non-flowing mode) is further demonstrated with stable cycle performance over 100 cycles at a large areal capacity of 6 mAh cm-2 and a pouch-type semi-solid full cell that remains functional even when it is mechanically abused. This work demystifies the SSLIBs and provides useful physical insights to further improve their performance and durability.

Multifunctional Cross-Linking Composite Binder Enables the Stable Performance of Si-Based Anodes for High-Energy-Density Lithium-Ion Batteries.

The intrinsic volumetric stress during cycling is the main obstacle for developing Si-based materials as high-energy-density lithium-ion battery anodes. Elastic binders have been demonstrated as an efficient approach to alleviate the stress of Si. Herein, we design a tough 3D hard/soft polymeric network (LPTS) using lithiated poly(acrylic acid), silk sericin, and highly branched tannic acid. Covalent cross-linking provides a robust mechanical strength to endure the large stress. The formed multiple hydrogen bonds with bonding energies between 3.46 and 25 kcal mol-1 can effectively dissipate the stress through sequential hydrogen bond disassociation. The multifunctional LPTS binder maintains the integrity of the Si-based electrodes during repeated discharging/charging. Additionally, Li+ can be transferred via a Li-conducting group (-COOLi), thereby enhancing the ionic conductivity of electrodes. Consequently, the Si/LPTS electrode exhibits an improved initial Coulombic efficiency and excellent durability over 400 cycles. Meanwhile, this binder is also suitable for Si-C anodes, enabling stable cycling at a high areal capacity >3.6 mAh cm-2 and delivering 72.2% capacity retention for the LFP||Si-C/LPTS full cell after 200 cycles. This study provides insight into developing efficient Si-based binders that are facile and low-cost for next-generation high-energy-density systems.

Preparation of photoreactive cathodes from copper-based metal-organic frameworks and their application in aqueous zinc-ion hybrid supercapacitors

To further enhance the energy density of aqueous zinc-ion hybrid supercapacitors, this paper verifies the feasibility of using copper catecholate (Cu-CAT) a copper-based metal-organic framework (MOF) characterized by strong broadband light absorption, good electrical conductivity, and a large specific surface area as a photoactive material. When used as the photoactive cathode in a Zn//Cu-CAT@CC aqueous zinc-ion hybrid supercapacitor, it can convert and store solar energy in the electrodes. Under sunlight, at a current density of 1 mA cm2, the device's areal capacity reaches 0.162 mAh cm2, an 89.1% increase over the storage capacity without light. This not only opens up new areas for the application of Cu-CAT materials but also offers more possibilities for the development of aqueous zinc-ion hybrid supercapacitors.

A Dual Salt/Dual Solvent Electrolyte Enables Ultrahigh Utilization of Zinc Metal Anode for Aqueous Batteries.

Rechargeable aqueous zincbatteriesare promising in next-generation sustainable energy storage. However, the low zinc (Zn) metal anode reversibility and utilization in aqueous electrolytes due to Zn corrosion and poor Zn2+ deposition kinetics significantly hinder the development of Zn-ion batteries. Here, a dual salt/dual solvent electrolyte composed of Zn(BF4)2/Zn(Ac)2 in water/TEGDME (tetraethylene glycol dimethyl ether) solvents to achieve reversible Zn anode at an ultrahigh depth of discharge (DOD) is developed. An "inner co-salt and outer co-solvent" synergistic effect in this unique dual salt/dual solvent system is revealed. Experimental results and theoretical calculations provide evidence that the ether co-solvent inhibits water activity by forming hydrogen bonding with the water and coordination effects with the proton in the outer Zn2+ solvation structure. Meanwhile, the anion of zinc acetate co-salt enters the inner Zn2+ solvation structure, thereby accelerating the desolvation kinetics. Strikingly, based on the electrolyte design, the zinc anode shows high reversibility at an ultrahigh utilization of 60% DOD with 99.80% Coulombic efficiency and 9.39 mAh cm-2 high capacity. The results far exceed the performance reported in electrolyte design work recently. The work provides fundamental insights into inner co-salt and outer co-solvent synergistic regulation in multifunctional electrolytes for reversible aqueous metal-ion batteries.

Synergistic Regulation of Sodium Metal Deposition Pattern Through Three-Dimensional Sodiophilic Gradient ZnO/Fe0.7Co0.3 Frameworks and Magnetic Fields for High-Performance Sodium Metal Batteries.

The application of sodium metal battery is hampered by the large volume change and uncontrollable top growth of Na metal. Herein, a dual strategy including constructing a three-dimensional gradient ZnO/Fe0.7Co0.3 (ZFC) framework of decreasing sodiophilic capability from bottom to top, and imposing magnetic fields based on magnetohydrodynamic (MHD) effect, is proposed to regulate the sodium deposition/stripping behavior and realize the bottom-up deposition of Na. Therefore, the ZFC framework under a magnetic field of 200 mT exhibits high electrochemical reversibility with a Coulombic efficiency of 99.77 % at 1 mA cm-2 and 1 mAh cm-2. Meanwhile, the ZFC composite anode (ZFC@Na) with the magnetic field of 200 mT delivers a small polarization voltage of approximately10 mV and long cycle life of more than 2500 h at 5 mA cm-2 and 5 mAh cm-2 in symmetric cells, along with good cycle stability in ZFC@Na||Na3V2(PO4)3 full cells (200 cycles at 1 C with a high capacity retention of 98 %). Accordingly, the novel strategy of combining magnetic fields and sodiophilic gradient frameworks provides a perspective to solve the issues of sodium dendrite growth.

Nitrogen-Doped TiO2- x(B)/MXene Heterostructures for Expediting Sulfur Redox Kinetics and Suppressing Lithium Dendrites.

Practical application of lithium-sulfur (Li-S) batteries is severely impeded by the random shuttling of soluble lithium polysulfides (LiPSs), sluggish sulfur redox kinetics, and uncontrollable growth of lithium dendrites, particularly under high sulfur loading and lean electrolyte conditions. Here, nitrogen-doped bronze-phase TiO2(B) nanosheets with oxygen vacancies (OVs) grown in situ on MXenes layers (N-TiO2- x(B)-MXenes) as multifunctional interlayers are designed. The N-TiO2- x(B)-MXenes show reduced bandgap of 1.10eV and high LiPSs adsorption-conversion-nucleation-decomposition efficiency, leading to remarkably enhanced sulfur redox kinetics. Moreover, they also have lithiophilic nature that can effectively suppress dendrites growth. The cell based on the N-TiO2- x(B)-MXenes interlayer under sulfur loading of 2.5mg cm-2 delivers superior cycling performance with a high specific capacity of 690.7 mAh g-1 over 600 cycles at 1.0 C. It still has a notable areal capacity of 6.15 mAh cm-2 after 50 cycles even under a high sulfur loading of 7.2mg cm-2 and a low electrolyte-to-sulfur (E/S) ratio of 6.4 µL mg-1. The Li-symmetrical battery with the N-TiO2- x(B)-MXenes interlayer showcases a low over-potential fluctuation with 21.0mV throughout continuous lithium plating/stripping for 1000h. This work offers valuable insights into the manipulation of defects and heterostructures to achieve high-energy Li-S batteries.

Multifunctional TiN-MXene-Co@CNTs Networks as Sulfur/Lithium Host for High-Areal-Capacity Lithium-Sulfur Batteries.

The inevitable shuttling and slow redox kinetics of lithium polysulfides (LiPSs) as well as the uncontrolled growth of Li dendrites have strongly limited the practical applications of lithium-sulfur batteries (LSBs). To address these issues, we have innovatively constructed the carbon nanotubes (CNTs) encapsulated Co nanoparticles in situ grown on TiN-MXene nanosheets, denoted as TiN-MXene-Co@CNTs, which could serve simultaneously as both sulfur/Li host to kill "three birds with one stone" to (1) efficiently capture soluble LiPSs and expedite their redox conversion, (2) accelerate nucleation/decomposition of solid Li2S, and (3) induce homogeneous Li deposition. Benefiting from the synergistic effects, the TiN-MXene-Co@CNTs/S cathode with a sulfur loading of 2.5 mg cm-2 could show a high reversible specific capacity of 1129.1 mAh g-1 after 100 cycles at 0.1 C, and ultralong cycle life over 1000 cycles at 1.0 C. More importantly, it even achieves a high areal capacity of 6.3 mAh cm-2 after 50 cycles under a sulfur loading as high as 8.9 mg cm-2 and a low E/S ratio of 5.0 μL mg-1. Besides, TiN-MXene-Co@CNTs as Li host could deliver a stable Li plating/striping behavior over 1000 h.

Inorganic Electrolyte Additive Promoting the Interfacial Stability for Durable Zn-Ion Batteries.

The development of Zn-ion batteries (ZIBs) is always hindered by the ruleless interface reactions between the solid electrode and liquid electrolyte, and seeking appropriate electrolyte additives is considered as a valid approach to stabilize the electrode/electrolyte interphases for high-performance ZIBs. Benefiting from the unique solubility of TiOSO4 in acidic solution, the composite electrolyte of 2m ZnSO4+30mm TiOSO4 (ZSO/TSO) is configured and its positive contribution to Zn//Zn cells, Zn//Cu cells, and Zn//NH4V4O10 batteries are comprehensively investigated by electrochemical tests and theoretical calculations. Based on the theoretical calculations, the introduction of TiOSO4 contributes to facilitating the desolvation kinetics of Zn2+ ions and guarantees the stable interface reactions of both zinc anode and NH4V4O10 cathode. As expected, Zn//Zn cells keep long-term cycling behavior for 3750h under the test condition of 1mA cm-2-1 mAh cm-2, Zn//Cu cells deliver high Coulombic efficiency of 99.9% for 1000 cycles under the test condition of 5mA cm-2-1 mAh cm-2, and Zn//NH4V4O10 batteries maintain reversible specific capacity of 193.8 mAh g-1 after 1700 cycles at 5 A g-1 in ZSO/TSO electrolyte. These satisfactory results manifest that TiOSO4 additive holds great potential to improve the performances of ZIBs.

An artificial sulfonated polyaniline coating for high stable and dendrite-free zinc anode

Designing the performance of artificial solid electrolyte interphase (ASEI) is critical for addressing issues at the Zn anode-electrolyte of aqueous zinc batteries (AZBs). Inspired by the anti-corrosion strategy of metal substrate, a self-doping sulfonated polyaniline (S-PANI) is constructed on the surface of zinc foil by a facile scraping method. The synergistic effect of nitrogen and sulfonic acid groups in S-PANI coating layer, accompanies microchannels in the polymer network is favorable for the fast Zn2+ ion transport, uniform and stable Zn deposition. As a result, the Zn anode with S-PANI coating can achieve high average coulombic efficiency of 98.0% over 150 cycles and superior cycling performance up to 1500 h at a 0.5 mA cm-2 and 0.5 mAh cm-2. Moreover, the full battery coupled with PTO organic cathode also demonstrates superior cycling stable performance. This work opens effective approach for the application of conductive polymer coating in Zn anode protection.

Vertical VOPO4·2H2O Nanosheets with Richly Exposed (200) Plane Enable Fast-Kinetics High-Mass-Loading Cathodes for Zn-Ion Batteries.

Extending the layer spacing of the (001) planes to regulate the mobility of Zn2+ is widely adopted to optimize the performance of VOPO4·2H2O cathode for zinc-ion batteries. However, the unique function originating from other planes is often neglected. Herein, an effective in situ conversion methodology is proposed for the synthesis of the (200) oriented growth of vertical VOPO4·2H2O nanosheets with oxygen vacancies (VOd-VOPO4). Theoretical simulation and ex situ characterizations collaboratively demonstrate that the richly exposed (200) plane with tetragonal channels can offer quick pathways for in-layer and cross-layer migration of Zn2+, exhibiting enhanced transfer kinetics with improved reversible capacity. Meanwhile, efficient electron migration in VOd-VOPO4 is guaranteed by the introduction of oxygen vacancies. Thus, the as-prepared VOd-VOPO4 harvests exceptional discharge capacity, impressive rate capability, and remarkable long-cycle stability at high mass loading. Notably, the VOd-VOPO4 electrode (15mg cm-2) provides a capacity of 213.5mAhg-1 with an ultrahigh areal capacity of 3.02 mAh cm-2 at 0.1 A g-1, showing great potential for applications. This study highlights the orientated growth strategy for facilitating ion storage and migration, offering novel perspectives on the development of high-performance electrodes and beyond.