Reversible Deposition/Dissolution of Double Hydroxides to Modulate Electrolyte pH Enabling High-Performance Aqueous Zinc-Ion Batteries.

Vanadium oxide has been extensively studied as a host of zinc ion intercalation but still suffers from low conductivity, dissolution, and byproduct accumulation during cycling. Here, we hydrothermally synthesize the VO2@MXene Ti3C2 (MV) composite and find that in the MV//3 M Zn(CF3SO3)2//Zn system, the double hydroxide Zn12(CF3SO3)9(OH)15·nH2O (ZCOH) uniformly covers VO2 during the charging process and dissolves reversibly during the discharge process. In situ X-ray diffraction of the MV combined with in situ pH measurements reveals that ZCOH acts as a pH buffer during cycling, which is beneficial to the cycling stability of batteries. And the theoretical calculation indicates that the decomposition energy required by ZCOH on the MV surface is lower than that on pure VO2, which is more conducive to ZCOH dissolution. The coin battery exhibits high-rate performance of 65.1% capacity retention at a current density of 15 A g-1 (compared to 0.6 A g-1) and a long cycling life of 20,000 cycles with a capacity retention of 80.7%. For a 22.4 mA h soft-packaged battery, its capacity remains at 72.1% after 2000 cycles. This work demonstrates the active role of ZCOH in the electrochemical process of VO2 and provides a new perspective for exploiting this mechanism to develop high-performance aqueous zinc-ion battery vanadium oxide cathode materials.

Limiting Interfacial Free Water and Proton Concentration by Hydrogel Electrolytes for Stable MoO3 Anode in a Proton Battery.

Aqueous rechargeable proton batteries are attractive due to the small ionic radius, light mass, and ultrafast diffusion kinetics of proton as charge carriers. However, the commonly used acidic electrolyte is usually very corrosive to the electrode material, which seriously affects the cycle life of the battery. Here, it is proposed that decreasing water activity and limiting proton concentration can effectively prevent side reactions of the MoO3 anode such as corrosion and hydrogen precipitation by using a lean-water hydrogel electrolyte. The as-prepared polyacrylamide (PAAM)-poly2-acrylamide-2-methylpropanesulfonic acid (PAMPS)/MnSO4 (PPM) hydrogel electrolyte not only has abundant hydrophilic groups that can form hydrogen bonds with free water and inhibit solvent-electrode interaction, but also has fixed anions that can maintain a certain interaction with protons. The assembled MoO3||MnO2 full battery can stably cycle over 500 times for ≈350 h with an unprecedented capacity retention of 100% even at a low current density of 0.5 A g-1. This work gives a hint that limiting free water as well as proton concentration is important for the design of electrolytes or interfaces in aqueous proton batteries.

Low-Electronegativity Cationic High-Entropy Doping to Trigger Stable Anion Redox Activity for High-Ni Co-Free Layered Cathodes in Li-Ion Batteries.

LiNi0.8 Co0.1 Mn0.1 O2 (NCM-811) exhibits the highest capacity in commercial lithium-ion batteries (LIBs), and the high Ni content (80 %) provides the only route for high energy density. However, the cationic structure instability arisen from the increase of Ni content (>80 %) limits the further increase of the capacity, and inevitable O2 release related to anionic structure instability hinders the utilization of anion redox activity. Here, by comparing various combinations of high-entropy dopants substituted Co element, we propose a low-electronegativity cationic high-entropy doping strategy to fabricate the high-Ni Co-free layered cathode (LiNi0.8 Mn0.12 Al0.02 Ti0.02 Cr0.02 Fe0.02 O2 ) that exhibits much higher capacity and cycling stability. Configurational disorder originated from cationic high-entropy doping in transition metal (TM) layer, anchors the oxidized lattice oxygen ((O2 )n- ) to preserve high (O2 )n- content, triggering the anion redox activity. Electron transfer induced by applying TM dopants with lower electronegativity than that of Co element, increases the electron density of O in TM-O octahedron (TM-O6 ) configuration to reach higher (O2 )n- content, resulting in the higher anion redox activity. With exploring the stabilization effect on both cations and anions of high-entropy doping and low-electronegativity cationic modified anion redox activity, we propose an innovative and variable pathway for rationally tuning the properties of commercial cathodes.

Guanxin V alleviates ventricular remodeling after acute myocardial infarction with circadian disruption by regulating mitochondrial dynamics.

PURPOSE: Circadian disruption has been a common issue due to modern lifestyles. Ventricular remodeling (VR) is a pivotal progressive pathologic change after acute myocardial infarction (AMI) and circadian disruption may have a negative influence on VR according to the latest research. Whether or not Guanxin V (GXV) has a positive effect on VR after AMI with circadian disruption drew our interest. METHODS: Rats were randomly divided into a sham group, an AMI group, an AMI with circadian disruption group, and an AMI with circadian disruption treated with the GXV group according to a random number table. RNA sequencing (RNA-Seq) was utilized to confirm the different expressed genes regulated by circadian disruption. Cardiac function, inflammation factors, pathological evaluation, and mitochondrial dynamics after the intervention were conducted to reveal the mechanism by which GXV regulated VR after AMI with circadian disruption. RESULTS: RNA-Seq demonstrated that NF-κB was up-regulated by circadian disruption in rats with AMI. Functional and pathological evaluation indicated that compared with the AMI group, circadian disruption was associcataed with deteriorated cardiac function, expanded infarcted size, and exacerbated fibrosis and cardiomyocyte apoptosis. Further investigation demonstrated that mitochondrial dynamics imbalance was induced by circadian disruption. GXV intervention reversed the inflammatory status including down-regulation of NF-κB. Reserved cardiac function, limited infarct size, and ameliorated fibrosis and apoptosis were also observed in the GXV treated group. GXV maintained mitochondrial fission/fusion imbalance through suppressed expression of mitochondrial fission-associated proteins. CONCLUSION: The study findings suggest that identified mitochondrial dysfunctions may underlie the link between circadian disruption and VR. GXV may exert cardioprotection after AMI with circadian disruption through regulating mitochondrial dynamics.

A mesoporous Al2O3 zincophilic sieve enables ultra-long lifespan of Zn-ion batteries.

The Zn dendrite growth and side reactions hinder the practical application of aqueous Zn-ion batteries. Here, a lactic acid-induced mesoporous Al2O3 (LA-MA) zincophilic sieve was constructed on a Zn anode to resolve these issues. The LA-MA layer with abundant mesoporous ion channels of 3.0 nm can regulate the solvation structure from [Zn2+(H2O)6]SO42- to more highly coordinated [Zn2+(H2O)5OSO32-] and restrain water-induced side reactions. Furthermore, the electrostatic attraction with zincophilic groups (CO, C-O) in the LA-MA layer has a positive effect on reducing the Zn2+ desolvation barrier and accelerating the Zn2+ diffusion. Under the synergism, the LA-MA@Zn symmetric cell exhibits over 5100 h at 0.25 mA cm-2. Impressively, an excellent capacity retention of 94.2% is achieved after 3500 cycles for the CNT/MnO2 cathode.

Stable Plating and Stripping of Lithium Metal Anodes through Space Confinement and Stress Regulation.

Lithium metal anodes suffer from enormous mechanical stress derived from volume changes during electrochemical plating and stripping. The utilization of derived stress has the potential for the dendrite-free deposition and electrochemical reversibility of lithium metal. Here, we investigated the plating and stripping process of lithium metal held within a cellular three-dimensional graphene skeleton decorated with homogeneous Ag nanoparticles. Owing to appropriate reduction-splitting and electrostatic interaction of nitrogen dopants, the cellular skeletons show micron-level pores and superior elastic property. As lithium hosts, the cellular skeletons can physically confine the metal deposition and provide continuous volume-derived stress between Li and collectors, thus meliorating the stress-regulated Li morphology and improving the reversibility of Li metal anodes. Consequently, the symmetrical batteries exhibit a stable cycling performance with a span life of more than 1900 h. Full batteries (NCM811 as cathodes) achieve a reversible capacity of 181 mA h g-1 at 0.5 C and a stable cycling performance of 300 cycles with a capacity retention of 83.5%. The meliorative behavior of lithium metal within the cellular skeletons suggests the advantage of a stress-regulating strategy, which could also be meaningful for other conversion electrodes with volume fluctuation.

An Ion-Sieving Janus Separator toward Planar Electrodeposition for Deeply Rechargeable Zn-Metal Anodes.

The irregular and random electrodeposition of zinc has emerged as a non-negligible barrier for deeply rechargeable aqueous zinc (Zn)-ion batteries (AZIBs), yet traditional texture regulation of the Zn substrate cannot continuously induce uniform Zn deposition. Here, a Janus separator is constructed via parallelly grown graphene sheets modified with sulfonic cellulose on one side of the commercial glass fiber separator through the spin-coating technique. The Janus separator can consistently regulate Zn growth toward a locked crystallographic orientation of Zn(002) texture to intercept dendrites. Furthermore, the separator can spontaneously repel SO4 2- and anchor H+ while allowing effective transport of Zn2+ to alleviate side reactions. Accordingly, the Zn symmetric cell harvests a long-term lifespan over 1400 h at 10 mA cm-2 /10 mAh cm-2 and endures stable cycling over 220 h even at a high depth of discharge (DOD) of 56%. The Zn/carbon nanotube (CNT)-MnO2 cell achieves an outstanding capacity retention of 95% at 1 A g-1 after 1900 cycles. Furthermore, the Zn/NH4 V4 O10 pouch cell with a Janus separator delivers an initial capacity of 178 mAh g-1 and a high capacity retention of 87.4% after 260 cycles. This work provides a continuous regulation approach to achieve crystallographic homogeneity of the Zn anode, which can be suitable for other metal batteries.

Crystal Plane Reconstruction and Thin Protective Coatings Formation for Superior Stable Zn Anodes Cycling 1300 h.

Some new insights into traditional metal pretreatment of anticorrosion for high stable Zn metal anodes are provided. A developed pretreatment methodology is employed to prefer the crystal plane of polycrystalline Zn and create 3.26 µm protective coatings mainly consisting of organic polymers and zinc salts on Zn foils (ROZ@Zn). In this process, Zn metal exhibits a surface-preferred (001) crystal plane proved by electron backscattered diffraction. Preferred (001) crystal planes and ROZ coatings can regulate Zn2+ diffusion, promote flat growth of Zn, and prevent side reactions. As a result, ROZ@Zn symmetrical cells exhibit superior plating/stripping performance over 1300 h. Impressively, it is significantly prolonged over 40 times in comparison to the bare Zn symmetric cell at 5 mA cm-2 . Moreover, Zn//MnO2  button cells have a high capacity retention of 96.3% after 1600 cycles and pouch cells have a high capacity 122 mAh g-1  after 200 cycle at 5 C. This work provides inspiration for high stable aqueous Zn metal batteries using the developed metal pretreatment of anticorrosion, which will be a viable, low-cost, and efficient technology. More interesting, it demonstrates the availability of reconstructing crystal planes by the largely heterogeneous reaction activation of the different crystal planes to H+ .

Enamel-like Layer of Nanohydroxyapatite Stabilizes Zn Metal Anodes by Ion Exchange Adsorption and Electrolyte pH Regulation.

The instability of Zn anode caused by severe dendrite growth and side reactions has restricted the practical applications of aqueous zinc-ion batteries (AZIBs). Herein, an enamel-like layer of nanohydroxyapatite (Ca5(PO4)3(OH), nano-HAP) is constructed on Zn anode to enhance its stability. Benefiting from the ion exchange between Zn2+ and Ca2+, the adsorption for Zn2+ in enamel-like nano-HAP (E-nHAP) layer can effectively guide Zn deposition, ensuring homogeneous Zn2+ flux and even nucleation sites to suppress Zn dendrites. Meanwhile, the low pH of acidic electrolyte can be regulated by slightly soluble nano-HAP, restraining electrolyte corrosion and hydrogen evolution. Moreover, the E-nHAP layer features high mechanical flexibility due to its enamel-like organic-inorganic composite nanostructure. Hence, symmetric cells assembled by E-nHAP@Zn show superior stability of long-term cycling at different current densities (0.1, 0.5, 1, 5, and 10 mA cm-2). The E-nHAP@Zn∥E-nHAP@Cu cell exhibits an outstanding cycling life with high Coulombic efficiency of 99.8% over 1000 cycles. Notably, the reversibility of full cell based on CNT/MnO2 cathode can be effectively enhanced. This work shows the potential of drawing inspiration from biological nanostructure in nature to develop stable metal electrodes.

Comparative Safety and Efficacy of Eight Antithrombotic Regimens for Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention.

Background: Antithrombotic therapy for patients with atrial fibrillation undergoing percutaneous coronary intervention is facing major treatment problems in clinical practice. Methods: We firstly conducted a Bayesian network meta-analysis to study the safety and efficacy of different antithrombotic regimens. Only randomized controlled trials from PubMed, Web of Science, Cochrane Central Register of Controlled Trials, Embase, and China National Knowledge Infrastructure were included in our study. The Bayesian random-effects model was used in this study. The primary safety and efficacy outcomes were major bleeding according to the criteria of Thrombolysis In Myocardial Infarction (TIMI) and trial-defined major adverse cardiovascular events, respectively. The secondary safety outcomes were combined TIMI major and minor bleeding, trial-defined primary bleeding events, and intracranial hemorrhage. The secondary efficacy outcomes were all-cause or cardiovascular mortality, myocardial infarction, stroke, stent thrombosis, and hospitalization. Results: Total of 11,532 patients from the five randomized controlled trials were analyzed, of whom 8,426 were male. Compared with vitamin K antagonist (VKA) plus P2Y12 inhibitor, the odds ratios (95% credible intervals) for TIMI major bleeding were 1.70 (0.77-3.80) for VKA plus dual antiplatelet therapy (DAPT), 1.20 (0.30-4.60) for rivaroxaban plus P2Y12 inhibitor, 1.00 (0.25-3.90) for rivaroxaban plus DAPT, 0.76 (0.21-2.80) for dabigatran plus P2Y12 inhibitor, 0.71 (0.25-2.10) for apixaban plus P2Y12 inhibitor, 1.40 (0.52-3.80) for apixaban plus DAPT, and 1.00 (0.27-4.00) for edoxaban plus P2Y12 inhibitor. For trial-defined major adverse cardiovascular events, compared with VKA plus P2Y12 inhibitor, the odds ratios (95% credible intervals) were 1.10 (0.61-2.00) for VKA plus DAPT, 1.20 (0.45-3.70) for rivaroxaban plus P2Y12 inhibitor, 1.10 (0.38-3.20) for rivaroxaban plus DAPT, 1.10 (0.43-3.10) for dabigatran plus P2Y12 inhibitor, 1.00 (0.47-2.20) for apixaban plus P2Y12 inhibitor, 0.99 (0.46-2.20) for apixaban plus DAPT, and 1.20 (0.43-3.40) for edoxaban plus P2Y12 inhibitor. Apixaban plus P2Y12 inhibitor was the highest-ranking of safety outcomes and VKA plus P2Y12 inhibitor was the highest-ranking of efficacy outcomes other than trial-defined major adverse cardiovascular events. Conclusion: Apixaban plus P2Y12 inhibitor seems to be linked with fewer bleeding complications while retaining antithrombotic efficacy. Moreover, for most efficacy indicators, the ranking of VKA plus P2Y12 inhibitor is still very high. Systematic Review Registration: [www.crd.york.ac.uk/prospero/], identifier [CRD42020149894].

Guanxin V alleviates acute myocardial infarction by restraining oxidative stress damage, apoptosis, and fibrosis through the TGF-ß1 signalling pathway.

BACKGROUND: Oxidative stress, apoptosis, and fibrosis have important roles in acute myocardial infarction, which is the main cause of global morbidity and mortality. Guanxin V significantly ameliorates acute myocardial infarction, the underlying mechanism, however, is still unclear. PURPOSE: In this study, we detected the anti-oxidative, anti-apoptotic, and anti-fibrosis effects of Guanxin V on acute myocardial infarction. METHODS: We used left anterior descending coronary artery ligation to construct an acute myocardial infarction model. Cardiac function, heart weight, infarction size, and histopathology were measured. Cardiomyocytes were treated with hydrogen peroxide to build an in vitro model. Cell apoptosis, fibrosis, and reactive oxygen species-related markers were tested. We observed the mitochondrial ultrastructure through transmission electron microscopy. The levels of collagens and TGF-ß1 signalling were measured. The lentiviral vector containing the full-length TGF-ß1 sequence was administered to investigate the rescue role of Guanxin V. RESULTS: Guanxin V significantly decreased apoptosis and inhibited oxidative stress damage and fibrosis in acute myocardial infarction. Hydrogen peroxide could stimulate cardiomyocytes to produce reactive oxygen species and Guanxin V could significantly reverse hydrogen peroxide-induced cell damage, inhibit oxidative stress damage, apoptosis, and fibrosis, and enhance mitochondrial dynamic balance. Mechanistically, Guanxin V attenuated oxidative stress damage, apoptosis, and fibrosis induced by the TGF-ß1 signalling pathway activation. CONCLUSIONS: Guanxin V effectively relieved apoptosis, oxidative stress damage, and fibrosis through down-regulating the TGF-ß1 signalling pathway, which enhances the knowledge of the cellular and molecular mechanism of Guanxin V in treating acute myocardial infarction.

Chemical Buffer Layer Enabled Highly Reversible Zn Anode for Deeply Discharging and Long-Life Zn-Air Battery.

Rechargeable alkaline Zn-air batteries (ZABs) are attracting extensive attention owing to their high energy density and environmental friendliness. However, the dilemma of Zn anode, composed of ineluctable passivation and dissolution problems, severely hinders the discharge and cycling performance of the battery. Herein, the authors propose a chemical buffer layer coated on Zn metal (CBL@Zn) anode, in which ZnO nanorods are uniformly dispersed in graphene oxide (GO), to improve the reversibility of Zn↔ZnO electrochemical conversion process. Benefiting from the cooperative effect of ZnO nanorods' nuclei role and GO's adsorption affinity, the electrochemical precipitation-dissolution behavior of insulated ZnO is chemically regulated and the Zn(OH)4 2- ions are effectively confined in the chemical buffer layer. Therefore, the symmetrical CBL@Zn-CBL@Zn coin cell achieves a superior stability of 100 cycles with quite low overpotential (30 mv). When paired with commercial catalysts to assemble alkaline ZABs for practical use, an ultra high depth of discharge (DODZn ) >98% and excellent 450-h long-term cycling performance are realized. This chemical buffer strategy can potentially provide a new insight for developing other highly reversible alkaline Zn-metal batteries.

Cellular and Molecular Mechanism of Traditional Chinese Medicine on Ventricular Remodeling.

Ventricular remodeling is related to the renin-angiotensin-aldosterone system, immune system, and various cytokines involved in inflammation, apoptosis, and cell signal regulation. Accumulated studies have shown that traditional Chinese medicine can significantly inhibit the process of ventricular remodeling, which may be related to the mechanism mentioned above. Here, we conducted a system overview to critically review the cellular and molecular mechanism of traditional Chinese medicine on ventricular remodeling. We mainly searched PubMed for basic research about the anti-ventricular remodeling of traditional Chinese medicine in 5 recent years, and then objectively summarized these researches. We included more than 25 kinds of Chinese herbal medicines including Qi-Li-Qian-Xin, Qi-Shen-Yi-Qi Pill, Xin-Ji-Er-Kang Formula, and Yi-Qi-Wen-Yang Decoction, and found that they can inhibit ventricular remodeling effectively through multi-components and multi-action targets, which are promoting the clinical application of traditional Chinese medicine.

High-Voltage and Super-Stable Aqueous Sodium-Zinc Hybrid Ion Batteries Enabled by Double Solvation Structures in Concentrated Electrolyte.

Aqueous sodium-zinc hybrid ion batteries are attracting extensive attention due to high energy density, low cost, and environmental friendliness. Unfortunately, there are still some drawbacks associated with the low voltage and cycle performance degradation that limit their practical application. Here, a concentrated aqueous electrolyte with solvation-modulated Zn2+ is reported that reduces the hydrogen evolution reaction on the surface of Zn metal, avoiding the generation of ZnO and uneven deposition. Accordingly, the Zn anode exhibits 1600 h Zn plating/stripping and ≈99.96% Coulombic efficiency after 700 cycles. In addition, solvation-modulated Na+ promotes the excellent structural stability of zinc hexacyanoferrate (ZnHCF) due to the rhombohedral-rhombohedral rather than rhombohedral-cubic phase transition. A ZnHCF//Zn full cell delivers an average voltage of 1.76 V and 98% capacity retention after 2000 cycles at 5 C rates.

Synergistic Catalysis by Single-Atom Catalysts and Redox Mediator to Improve Lithium-Oxygen Batteries Performance.

Lithium-oxygen (Li-O2 ) batteries with ultrahigh theoretical energy density have attracted widespread attention while there are still problems with high overpotential and poor cycle stability. Rational design and application of efficient catalysts to improve the performance of Li-O2 batteries is of significant importance. In this work, Co single atoms catalysts are successfully combined with redox mediator (lithium bromide [LiBr]) to synergistically catalyze electrochemical reactions in Li-O2 batteries. Single-atom cobalt anchored in porous N-doped hollow carbon spheres (CoSAs-NHCS) with high specific surface area and high catalytic activity are utilized as cathode material. However, the potential performances of batteries are difficult to adequately achieve with only CoSAs-NHCS, owing to the blocked electrochemical active sites covered by insulating solid-state discharge product Li2 O2 . Combined with LiBr as redox mediator, the enhanced OER catalytic effect extends throughout all formed Li2 O2 during discharge. Meantime, the certain adsorption effect of CoSAs-NHCS on Br2 and Br3 - can reduce the shuttle of RMox . The synergistic effect of Co single atoms and LiBr can not only promote more Li2 O2 decomposition but also reduce the shuttle effect by absorbing the oxidized redox mediator. Li-O2 batteries with Co single atoms and LiBr achieve ultralow overpotential of 0.69 V and longtime stable cyclability.

Effects of Traditional Chinese Medication-Based Bioactive Compounds on Cellular and Molecular Mechanisms of Oxidative Stress.

The oxidative stress reaction is the imbalance between oxidation and antioxidation in the body, resulting in excessive production of oxygen free radicals in the body that cannot be removed, leading to excessive oxidation of the body, and causing damage to cells and tissues. A large number of studies have shown that oxidative stress is involved in the pathological process of many diseases, so inhibiting oxidative stress, that is, antioxidation, is of great significance for the treatment of diseases. Studies have shown that many traditional Chinese medications contain antioxidant active bioactive compounds, but the mechanisms of those compounds are different and complicated. Therefore, by summarizing the literature on antioxidant activity of traditional Chinese medication-based bioactive compounds in recent years, our review systematically elaborates the main antioxidant bioactive compounds contained in traditional Chinese medication and their mechanisms, so as to provide references for the subsequent research.

Deep Subdomain Adaptation Network for Image Classification.

For a target task where the labeled data are unavailable, domain adaptation can transfer a learner from a different source domain. Previous deep domain adaptation methods mainly learn a global domain shift, i.e., align the global source and target distributions without considering the relationships between two subdomains within the same category of different domains, leading to unsatisfying transfer learning performance without capturing the fine-grained information. Recently, more and more researchers pay attention to subdomain adaptation that focuses on accurately aligning the distributions of the relevant subdomains. However, most of them are adversarial methods that contain several loss functions and converge slowly. Based on this, we present a deep subdomain adaptation network (DSAN) that learns a transfer network by aligning the relevant subdomain distributions of domain-specific layer activations across different domains based on a local maximum mean discrepancy (LMMD). Our DSAN is very simple but effective, which does not need adversarial training and converges fast. The adaptation can be achieved easily with most feedforward network models by extending them with LMMD loss, which can be trained efficiently via backpropagation. Experiments demonstrate that DSAN can achieve remarkable results on both object recognition tasks and digit classification tasks. Our code will be available at https://github.com/easezyc/deep-transfer-learning.

Aqueous Rechargeable Li+ /Na+ Hybrid Ion Battery with High Energy Density and Long Cycle Life.

The practical application of aqueous rechargeable batteries is hampered by the low energy density and poor cycle stability, which mostly arises from the corrosion of cathode current collector, exfoliation of active material, and narrow electrochemical stability window of aqueous electrolyte. A light-weight and low-cost cathode current collector composed of graphite and carbon nanotube coated on nylon membrane exhibiting corrosion resistance and strong adhesion is developed. Also, a modified aqueous electrolyte with the addition of urea whose window is expanded to ≈3.2 V is developed that contributes to the formation of solid-electrolyte interphase on surfaces of electrodes. LiMn2 O4 /NaTi2 (PO4 )3 Li+ /Na+ hybrid ion battery using such aqueous electrolyte and current collector is demonstrated to cycle up to 10 000 times with low cost (60 dollars per kWh) and high energy density (100 Wh kg-1 ) for stationary energy storage and electronic vehicles applications.

Guiding Smooth Li Plating and Stripping by a Spherical Island Model for Lithium Metal Anodes.

Lithium metal anodes are considered as promising candidates for next-generation high-energy-density batteries. However, the dendrite formation of Li metal anodes during charge-discharge results in some serious issues. Herein, we show a simple way to flatten the Li metal deposition surface on Ag-modified Cu foil using a spherical island model. In this model, Ag nuclei induce the deposition of Li atoms with low nucleation potentials at the initial heterogeneous nucleation stage. Then, Li homogeneously grows around the spherical islands and these regular islands overlap each other and form a flat Li surface. On the bare Cu foil surface, the Li growth behavior is random, and the deposition surface is porous and covered with dendrites. Stable long-term plating/stripping of a symmetric battery over 800 h at 1 mA cm-2 was achieved. Moreover, the super flat Li structure can be achieved by constructing islands into a three-dimensional (3D) current collector using the spherical island model. Benefiting from the spherical island model, Li||LiFePO4 and Li||O2 batteries with this 3D anode structure can obtain a stable performance.

A High-Energy and Long-Life Aqueous Zn/Birnessite Battery via Reversible Water and Zn2+ Coinsertion.

Aqueous rechargeable Zn/birnessite batteries have recently attracted extensive attention for energy storage system because of their low cost and high safety. However, the reaction mechanism of the birnessite cathode in aqueous electrolytes and the cathode structure degradation mechanics still remain elusive and controversial. In this work, it is found that solvation water molecules coordinated to Zn2+ are coinserted into birnessite lattice structure contributing to Zn2+ diffusion. However, the birnessite will suffer from hydroxylation and Mn dissolution with too much solvated water coinsertion. Through engineering Zn2+ primary solvation sheath with strong-field ligand in aqueous electrolyte, highly reversible [Zn(H2 O)2 ]2+ complex intercalation/extraction into/from birnessite cathode is obtained. Cathode-electrolyte interface suppressing the Mn dissolution also forms. The Zn metal anode also shows high reversibility without formation of "death-zinc" and detrimental dendrite. A full cell coupled with birnessite cathode and Zn metal anode delivers a discharge capacity of 270 mAh g-1 , a high energy density of 280 Wh kg-1 (based on total mass of cathode and anode active materials), and capacity retention of 90% over 5000 cycles.