Reversible Metal Research Articles

Interfacial double-coordination effect reconstructing anode/electrolyte interface for long-term and highly reversible Zn metal anodes

The highly reversible electrochemical deposition and dissolution of zinc metal anode is a critical feature for the practical application of aqueous zinc-ion batteries (ZIBs). Nevertheless, this process is seriously hindered by the uncontrollable electrodeposition and interfacial side reactions caused by thermodynamically unstable anode/electrolyte interface (AEI). Guided by the electrode/electrolyte interface chemistry, thiamine hydrochloride (TH) as a novel additive is added into traditional ZnSO4 (ZS) electrolyte to induce sustained reversible Zn deposition/stripping. Spectroscopic characterizations and electrochemical tests reveal that TH can adsorbed on the anode surface owning to the strong double-coordination effect between N, S atoms and Zn atoms via Zn-N and Zn-S chemical bonds. In addition, there are polar hydroxyl groups in the TH molecular structure which can form hydrogen bonds with water molecules. Thus, the adsorbed TH layer can not only guide the diffusion of Zn2+ ions and achieve dendrite-free electrodeposition process, but also prevent intimate contact between water and anode to suppress the occurrence of interface side reactions. Based on these benefits, the TH additive achieves an ultra-long stable cycle lifespan to 2045 h at 1 mA cm−2 and 1 mAh cm−2. Even at a higher current density of 5 mA cm−2, prolonged cycling performance about 773 h is demonstrated. Besides, the assembled Zn//NVO full cells reveal excellent capacity retention and rate performance under practical conditions, highlighting the efficient and reliable coordination effect of TH additive at the AEI.

Tandem desolvation effect enables highly reversible Zn metal anodes

Metallic Zn, with its affordability and safety, has been regarded as an attractive anode for aqueous batteries but has suffered from dendrite growth. Here, a tandem desolvation strategy is proposed to stabilize Zn metal anodes by a 4-pyridinecarboxamide (PCA) additive as an example. Theoretical and experimental characterizations demonstrate that the PCA molecular layer adsorbs on the anode surface, as well as the derived ZnS/N-rich solid electrolyte interphase (SEI), can sequentially promote the desolvation of hydrated Zn2+ during the electrodeposition process. This phenomenon, known as the tandem desolvation effect, effectively suppresses Zn dendrite growth and achieves the highest utilization rate of 96.7 % in the Zn||Zn cells. Specifically, the Zn||Zn cells can operate at 10, 20, and 50 mA cm−2 with a deposition capacity of 17 mAh cm−2 for 1200, 1000, and 850 h, respectively. Additionally, the constructed PANI||Zn pouch cells also achieve excellent cycle performance, confirming the feasibility of the tandem desolvation effect. This work enriches the understanding of Zn electrodeposition and provides a new perspective for the development of highly reversible metal anodes.

Anti-perovskite nitrides as chemically stable lithiophilic materials for highly reversible Li plating/stripping

Constructing structured anodes with lithiophilic materials has emerged as an essential strategy to stabilize Li deposition and accomplish highly reversible Li metal batteries (LMBs). Nevertheless, a lithiophilic material, which meets the requirements of low cost, excellent electronic conductivity and especially chemical stability, is still absent. Herein, we report the discovery of a new class of lithiophilic anti-perovskite nitrides MNNi3 (M=Zn, Cu, In) that not only are cost-effective and highly conductive, but also possess excellent stability against Li metal. More specifically, electrochemical tests in combination with density functional theory (DFT) calculations reveal that the lithiophilicity of MNNi3 arises from unique chemical/physical adsorption rather than the previously proposed alloying or conversion reaction mechanisms. The MNNi3@CC enabled symmetric cells exhibit better rate capability and longer cycle life than the cells with pure carbon cloth and Ni3N@CC. More importantly, the excellent electrochemical performances of MNNi3 anodes are also verified by ZnNNi3@CC in a LiFePO4 coupled full cell with minimal capacity degradation of 28% in 1500 cycles under the charge/discharge current of 1C. Beyond offering a new type of non-reactive lithiophilic materials to outstanding achieve battery performance, this study deepens the understanding of the lithiophilic nature of different metal nitrides, which paves a way for developing highly reversible lithium metal anode.

Trace alcohol ether electrolytes with dual-site hydrogen bonds and modulated solvation structures for ultralong-life zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are highly regarded for their affordability, stability, safety, and eco-friendliness. Nevertheless, their practical application is hindered by severe side reactions and the formation of zinc (Zn) dendrites on the Zn metal anode surface. In this study, we employ tetrahydrofuran alcohol (THFA), an efficient and cost-effective alcohol ether electrolyte, to mitigate these issues and achieve ultralong-life AZIBs. Theoretical calculations and experimental findings demonstrate that THFA acts as both a hydrogen bonding donor and acceptor, effectively anchoring H2O molecules through dual-site hydrogen bonding. This mechanism restricts the activity of free water molecules. Moreover, the two oxygen (O) atoms in THFA serve as dual solvation sites, enhancing the desolvation kinetics of [Zn(H2O)6]2+ and improving the deposition dynamics of Zn2+ ions. As a result, even trace amounts of THFA significantly suppress adverse reactions and the formation of Zn dendrites, enabling highly reversible Zn metal anodes for ultralong-life AZIBs. Specifically, a Zn-based symmetric cell containing 2 % THFA achieves an ultralong cycle life of 8,800 h at 0.5 mA cm−2/0.5 mAh cm−2, while a Zn//VO2 full cell containing 2 % THFA maintains a remarkable 80.03 % capacity retention rate at 5 A g−1 over 2,000 cycles. This study presents a practical strategy to develop dendrite-free, cost-effective, and highly efficient aqueous energy storage systems by leveraging alcohol ether compounds with dual-site hydrogen bonding capabilities.

Highly Reversible Zn Metal Anode Enabled by Interfacial Water Pocket

Highly Reversible Zn Metal Anode Enabled by Interfacial Water Pocket

An Ion-Pumping Quasi-Solid Electrolyte Enabled by Electrokinetic Effects for Stable Aqueous Zinc Metal Batteries.

The practical application of aqueous zinc (Zn) metal batteries (ZMBs) is hindered by the complicated hydrogen evolution, passivation reactions, and dendrite growth of Zn metal anodes. Here, an ion-pumping quasi-solid electrolyte (IPQSE) with high Zn2+ transport kinetics enabled by the electrokinetic phenomena to realize high-performance quasi-solid state Zn metal batteries (QSSZMBs) is reported. The IPQSE is prepared through the in situ ring-opening polymerization of tetramethylolmethane-tri-β-aziridinylpropionate in the aqueous electrolyte. The porous polymer framework with high zeta potential provides the IPQSE with an electrokinetic ion-pumping feature enabled by the electrokinetic effects (electro-osmosis and electrokinetic surface conduction), which significantly accelerates the Zn2+ transport, reduces the concentration polarization and overcomes the diffusion-limited current. Moreover, the Zn2+ affinity of the polymer and hydrogen bonding interactions in the IPQSE changes the Zn2+ coordination environment and reduces the amount of free H2O, which lowers the H2O activity and inhibits H2O-induced side reactions. Consequently, the highly reversible and stable Zn metal anodes are achieved. The assembled QSSZMBs based on the IPQSE display excellent cycling stability with high capacity retention and Coulombic efficiency. The high-performance quasi-solid state Zn metal pouch cells are demonstrated, showing great promise for the practical application of the IPQSE.

Water‐Lean Inner Helmholtz Plane Enabled by Tetrahydropyran for Highly Reversible Zinc Metal Anode

AbstractThe reversibility and stability of zinc (Zn) metal anode are closely related to inner Helmholtz plane (IHP) chemistry. The H2O‐rich IHP raises severe parasitic reactions and irregular Zn deposition, impeding the practical utility of Zn anode in aqueous Zn‐ion batteries (AZIBs). In this study, tetrahydropyran (THP), a five‐carbon heterocyclic ether with permanent dipole moment and hydrophobic characteristic, is introduced as a self‐adsorptive additive to reshape the IHP. It squeezes out partial H2O molecules and forms a H2O‐lean IHP, benefitting for alleviating active H2O decomposition and improving the stability of Zn anode. Moreover, the adsorbed THP induces the preferential nucleation of Zn (002) plane, facilitating dendrite‐free growth and improving the reversibility of Zn anode. Consequently, the Zn||Zn symmetric cell enables to cycle over 3600 h at 5 mA cm−2@ 1 mAh cm−2. The Zn||Cu half‐cell can stably cycle over 400 cycles with 99.9% coulombic efficiency even under harsh test conditions (10 mA cm−2@5 mAh cm−2) with 30 µm Zn foil. The Zn||NH4V4O10 full cell maintains 92.6% capacity retention after 800 cycles at 1 A g−1 and the Zn||I2 full cell enables to perform steadily over 10000 cycles with a capacity decay rate of merely 0.003% per cycle at 5 C.

Design of a dynamically switchable metamaterial solar heating and daytime radiative cooling device based on reversible metal electrodeposition

Abstract The combination of daytime radiative cooling and solar heating can regulate the temperature of buildings in all seasons, which is vital to achieving energy savings. However, achieving a dynamic and efficient switch between radiative cooling and solar heating states is still challenging. The reversible metal electrodeposition is a promising electrochromic (EC) technology that can dynamically manipulate the visible and infrared spectrum by depositing a nanoscale metal layer. By combining it with a delicate nanostructure design, reconfigurable daytime radiative cooling and solar heating states can be achieved. In this work, a metamaterial EC device capable of efficiently switching between high solar reflectance (91.73%) and high solar absorptance (95.41%) via reversible silver layer electrodeposition has been developed. This device consists of a top layer, which is a visible transparent electrode of indium tin oxide covered with an ultrathin platinum film, an electrolyte in the middle, and a metamaterial absorber based on a metal/dielectric multilayered structure at the bottom. Afterward, we analyze the spectrum of each part of the device and carry out a parametric study on the practical performance with different ambient temperatures and convective heat transfer coefficients. The average solar reflectance of the device in the radiative cooling state is 93.41% within the range of 0.3–2.5 μm. In the solar heating mode, the average solar absorptance of the device reaches 95.46%. Numerical simulations show that the device in the cooling mode achieves a temperature drop of 5 °C–9.8 °C and an average cooling power of 140.8 W m − 2 . The device in heating mode achieves a maximum temperature rise of 45 °C and a maximum heating power of 700 W m − 2 . This work provides a feasible design for solar heating and daytime radiative cooling switching devices, which is promising in applications like energy-saving buildings, wearable devices, electric vehicles and other outdoors facilities.

High Entropy Alloys as Bifunctional Catalysts for Reversable Metal Air Batteries

The development of stable non-noble metal bifunctional catalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are essential for technologies such as reversible metal air batteries. We have shown that synthesis of high entropy alloy nanoparticles formed through a novel synthesis method where metal precursor containing aqueous nanodroplets freely diffusing in an emulsion solution, collide with an electrode surface and the metal precursors are reduced, thus forming a homogeneous particle containing the predetermined metal composition. Afterwards, the particles are annealed at a low temperature causing a phase separation of the metals, forming a metal nanoparticle that is surrounded by a stabilizing metal oxide. We have demonstrated that equimolar Fe, Ni, Co, Cr, and Mn solutions produce bifunctional FeNiCo metal nanoparticles surrounded by CrMnOx that are very active for both OER and ORR. The synthesis technique also affords the flexibility to tailor composition of the nanoparticles and potentially provide access to previously difficult to synthesize compositions and may alter the electrocatalytic reaction pathways and activities.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525

(Invited) Engineering Nanocomposite Substrates for Metal Deposition

Reversible metal plating is at the heart of aqueous based energy storage. Since virtually all metal anodes, e.g., Fe, and Zn, operate outside the stability window of water, it is thus essential to minimize their surface area by controlling the nucleation and growth during deposition and the pit formation during stripping.While epitaxial growth has shown promise as exemplified by the horizontal zinc deposition on graphene, an approximate heteroepitaxy, we will focus our effort in developing a nanocomposite substrate that promotes uniform nucleation sites and fast surface transport. The strategy is potentially highly scalable to address the need for large scale storage. Recently, we have shown that a nanocomposite substrate can induce single crystalline Li growth. By reacting FeF3 with Li, a nanocomposite of Fe and LiF is formed which features Fe nanoparticles of < 2 nm in size uniformly distributed in a matrix of LiF. Despite the global lithiophobility of the substrate, nano Fe domains provide energetically uniform nucleation sites for Li deposition while LiF enables rapid surface transport. Corporative merging of neighboring seeds lead to the formation of single crystalline Li. Unlike single crystal substrates, the nanocomposite features uniformly distributed, energetically equivalent sites for nucleation.We have adopted a similar strategy for Fe and Zn deposition. Preliminary results show that significantly improved macroscopic uniformity is achieved with the nanocomposite substrate. We will discuss materials requirements for operation in an aqueous environment and the general applicability of the approach for other materials.

Non-rigid metal–oxygen bonding empowered nitrate reduction on ruthenium catalysts

Electrocatalytic nitrate reduction (NitRR) offers exciting potential for mass production of ammonia (NH3) from renewables. However, the rigidity of metal−ligand bonds in most electrocatalysts renders them unable to survive the structural transformations required for NitRR. Herein, we establish a type of non-rigid metal−oxygen bonds by employing graphene oxide (GO) sheets as a 'micron-scale' ligand for transition metals (TM). Because of being confined to the interfaces between GO and TM, the oxygenated groups in GO can associate with and dissociate from the TM in response to reaction dynamics. As a proof-of-concept demonstration, an electrocatalyst was developed by dispersing nanoscale ruthenium (Ru) on graphene oxide (GO) and utilizing two-dimensional MXene to compensate for the low electrical conductivity of GO. This electrocatalyst exhibits a maximum NH3 yield of over 5 mg cm−2 h−1, with almost 100 % current-to-NH3 efficiency, far outperforming the performance of most reported Ru-based materials. What's even more remarkable is the achievement of a record-breaking performance: a 200-hour stable electrolysis with a NH3 yield of 40.2 mg cm−2 h−1, using a membrane electrode reactor. Our experimental and theoretical investigations further reveal the non-rigidity of the Ru–O bonds and how they self-regulate to adapt to diverse intermediates involved in NitRR. This work provides an approach to fabricate a high-performance electrocatalyst featuring reversible and non-rigid metal−oxygen bonds, opening new possibilities for practical nitrate electrolysis.

Leveraging Ion Pairing and Transport in Localized High‐Concentration Electrolytes for Reversible Lithium Metal Anodes at Low Temperatures

Leveraging Ion Pairing and Transport in Localized High‐Concentration Electrolytes for Reversible Lithium Metal Anodes at Low Temperatures

Reversible metal cluster formation on Nitrogen-doped carbon controlling electrocatalyst particle size with subnanometer accuracy

Copper and nitrogen co-doped carbon catalysts exhibit a remarkable behavior during the electrocatalytic CO2 reduction (CO2RR), namely, the formation of metal nanoparticles from Cu single atoms, and their subsequent reversible redispersion. Here we show that the switchable nature of these species holds the key for the on-demand control over the distribution of CO2RR products, a lack of which has thus far hindered the wide-spread practical adoption of CO2RR. By intermitting pulses of a working cathodic potential with pulses of anodic potential, we were able to achieve a controlled fragmentation of the Cu particles and partial regeneration of single atom sites. By tuning the pulse durations, and by tracking the catalyst’s evolution using operando quick X-ray absorption spectroscopy, the speciation of the catalyst can be steered toward single atom sites, ultrasmall metal clusters or large metal nanoparticles, each exhibiting unique CO2RR functionalities.

Ultra-adherable dual-network conductive hydrogel with moistening and anti-freezing as a flexible sensor

Multifunctional conductive hydrogels have shown great promise in wearable flexible sensor application. This paper reported a dual-network self-healing electrically hydrogel through simple one-pot polymerization, which initiated from Ag+- lignin nanoparticles (LNPs) -APS redox system. Owing to the reversible metal coordination and hydrogen bonding cross-linked among polymer network, the resulting conductive hydrogel-based sensor demonstrated excellent stretchable, adhesion strength, and fatigue resistance. Additionally, the complex hydrogel (PHEMA/SA/Gly/Ca) incorporating with glycerol and CaCl2 in particular exhibited strong frost resistance (−40oC) and moisturizing qualities to monitor the motion signals in the low-temperature dry state. Therefore, the fabricated wearable sensor is sufficient for detecting large and small human motions, suggesting lots of promising applications in electronic skins, information identification and encryption, and human-motion monitoring.

Solvethermal synthesis and thermochromic properties of CaF2@VO2-based core-shell structure composites

Vanadium oxide (VO2)-based core-shell structures exhibit unique properties due to their reversible metal–insulator transition (MIT). As a result, numerous applications on the device level have been reported in the literature. However, since VO2 are multivalent compounds, the controllable preparation of VO2 core-shell-based particles is quite challenging. Along these lines, in this work, to overcome these limitations, the growth mechanism of VO2 shells on spherical substrates was systematically investigated. More specifically, the CaF2@VO2 core-shell microspheres were fabricated successfully by applying the solvent/hydrothermal-calcination method for the first time, while the phase evolution and morphological characteristics of the preparation process were studied in detail. From the obtained results, it was demonstrated that the composite particle's morphology and phase structure strongly depend on the activator, solvent, annealing atmosphere, and the annealing temperature. In addition, the infrared transmittance of the prepared CaF2@VO2(M) coating exhibited a decrease of 34.08 % during the metal–semiconductor phase transition in the 4–12 μm wavelength. Compared with the VO2 coatings and the uncoated CaF2/VO2 coatings, the transmittance conversion performance (ΔT) of the CaF2@VO2(M) coating was also increased by 22.62 % and 21.22 %, respectively.

Adaptive infrared radiation modulator using reversible metal electrodeposition with silicon carbide-based fabry-perot cavity

Conventional materials that statically modulate radiation in the infrared (IR) region of the electromagnetic spectrum underpin the performance of many entrenched technologies. The development of their adaptive variants, whereby the IR radiation properties dynamically change as a response to external stimuli, has emerged as an important unfulfilled scientific challenge. Here, by combining the silicon carbide (SiC)-based Fabry-Perot (FP) cavity effect with the traditional reversible metal electrodeposition device (RMED), where the FP cavity is used as a color filter to emit a particular wavelength and the RMED is used to reversibly modulate IR radiation, we develop an adaptive IR radiation modulator with large and uniform IR emissivity tunability (Δε ≥ 0.579) in the 3–14 µm region. A specific structural color which is a function of the SiC thickness can be simultaneously displayed when the modulator is in the low-emissivity mode. By varying the SiC thickness from 100 to 180 nm, a full gamut of colors spanning the entire visible spectrum can be achieved. Additionally, the modulator can exhibit fantastic patterns consisting of different structural colors with simple designs achieved. We believe that our findings may open opportunities for camouflage in multispectral detection and many technologies related to IR radiation management.

Recent Developments of Next-generation Smart Window using Metal Electrodeposition

Due to the energy and environmental crisis, indoor energy efficiency is of great importance. One of the solutions to cope with the problem is adopting a device with energy-saving functionality. From that perspective, smart window technology has received the foremost attention as of great potential, because it could modulate the solar energy stream such as light and heat. In addition to that, smart windows could offer visual aesthetic operation to our daily lives. Despite many technical attempts, no technology has been commercialized abruptly due to the restrictions or disadvantages. One of the rising options is a smart window based on reversible metal electrodeposition, as metal electrodeposits possess high contrast with color neutrality, and high coloration efficiency for privacy state. Since 2017, reversible metal electrodeposition-based smart window technology has been emerging, and advancing in terms of cycling, bistability, and color uniformity. This review aims to summarize the current technological trends and directions for the development of reversible metal electrodeposition-based smart window technologies.

T‐Nb2O5 Surface Coating Enables a Stable Zinc Anode

The surface reactions of zinc anode, including dendrite formation, corrosion, and passivation, hinder the aqueous zinc‐ion batteries. Surface engineering is one effective strategy for zinc protection. Herein, a high dielectric constant and stable and easily prepared T‐Nb2O5 first demonstrate as the surface coating for zinc anode. The hydrophilic T‐Nb2O5 coating can restrict the migration path of zinc ions and induce the bottom‐up orderly deposition of zinc ions instead of disordered deposition. The T‐Nb2O5 coating zinc anode (T‐Nb2O5/Zn) shows improved electrochemical performance. The voltage of T‐Nb2O5/Zn symmetric cell is stable in the long cycle of 1600 h and about 50 mV in the first 20 h and 25 mV in the last 20 h. After 150 cycles, the discharge capacity of T‐Nb2O5/Zn || MnO2 full battery is 209 mAh g−1, showing a capacity retention rate of 94%. The design of T‐Nb2O5 coating provides an attractive strategy for stable and reversible aqueous zinc metal batteries.

Highly Reversible Zn Metal Anode Securing by Functional Electrolyte Modulation

AbstractThe stability of the Zn metal anode is significantly affected by the various parasitic reactions during plating/stripping. Here, sodium 4‐aminobenzenesulfonate (SABS) is a functional electrolyte additive to modulate the electrode/electrolyte interface to protect the Zn metal. An electrical double layer (EDL) reconstruction of the interface is affected by providing hydrogen bond sites through nitrogen and oxygen elements with lone pair electrons in SABS molecules. These strong hydrogen bonds not only limit the corrosion of free H2O molecules on the surface of Zn anode but also promote the desolvation process. Besides, the SABS can be further in situ decomposed into a solid electrode/electrolyte interface (SEI) layer to regulate the plating/stripping behavior of Zn2+. As a result, based on the synergism of organic–inorganic hybrid SEI layer and the EDL reconstruction, the Zn//Zn symmetric cells exceptionally survive lasting for 6500 hours at 1 mA cm−2 and 1 mAh cm−2, and over 900 cycles even at 40 mA cm−2 and 10 mAh cm−2. The Zn‐I2 full cell maintains excellent cycle stability of 92.4% after 20000 cycles. Remarkably, the pouch cell maintains a capacity retention of over 99.1% (63 mAh) for 820 cycles at 5 mA cm−2.

Highly reversible transition metal migration in superstructure-free Li-rich oxide boosting voltage stability and redox symmetry

The further practical applications of Li-rich layered oxides are impeded by voltage decay and redox asymmetry, which are closely related to the structural degradation involving irreversible transition metal migration. It has been demonstrated that the superstructure ordering in O2-type materials can effectively suppress voltage decay and redox asymmetry. Herein, we elucidate that the absence of this superstructure ordering arrangement in a Ru-based O2-type oxide can still facilitate the highly reversible transition metal migration. We certify that Ru in superstructure-free O2-type structure can unlock a quite different migration path from Mn in mostly studied cases. The highly reversible migration of Ru helps the cathode maintain the structural robustness, thus realizing terrific capacity retention with neglectable voltage decay and inhibited oxygen redox asymmetry. We untie the knot that the absence of superstructure ordering fails to enable a high-performance Li-rich layered oxide cathode material with suppressed voltage decay and redox asymmetry.