Suppressing metal corrosion through identification of optimal crystallographic plane for Zn batteries.

Direct use of metals as battery anodes could significantly boost the energy density, but suffers from limited cycling. To make the batteries more sustainable, one strategy is mitigating the propensity for metals to form random morphology during plating through orientation regulation, e.g., hexagonal Zn platelets locked horizontally by epitaxial electrodeposition or vertically aligned through Zn/electrolyte interface modulation. Current strategies center around obtaining (002) faceted deposition due to its minimum surface energy. Here, benefiting from the capability of preparing a library of faceted monocrystalline Zn anodes and controlling the orientation of Zn platelet deposits, we challenge this conventional belief. We show that while monocrystalline (002) faceted Zn electrode with horizontal epitaxy indeed promises the highest critical current density, the (100) faceted electrode with vertically aligned deposits is the most important one in suppressing Zn metal corrosion and promising the best reversibility. Such uniqueness results from the lowest electrochemical surface area of (100) faceted electrode, which intrinsically builds upon the surface atom diffusion barrier and the orientation of the pallets. These new findings based on monocrystalline anodes advance the fundamental understanding of electrodeposition process for sustainable metal batteries and provide a paradigm to explore the processing-structure-property relationships of metal electrodes.

Safe and Effective Blood Preservation Through Acute Normovolemic Hemodilution and Low-Dose Tranexamic Acid in Open Partial Hepatectomy.

Objective: In this study, we evaluated the efficacy of tranexamic acid (TXA) and acute normovolemic hemodilution (ANH) with 6% hydroxyethyl starch (130/0.4) in minimizing blood loss during open partial liver resection. Coagulation function was assessed using thromboelastography (TEG) and hemostasis tests, while renal function changes were tracked through serum creatinine values post-surgery. Methods: Thirty patients undergoing open partial liver resection were allocated to two groups: Group T received TXA + ANH, and Group A received ANH alone. Blood was drawn from the radial artery under general anesthesia. Both groups received peripheral vein injections of 6% hydroxyethyl starch 130/0.4. Group T additionally received intravenous TXA. Primary outcomes included blood loss and allogeneic blood transfusions. TEG assessed coagulation status and renal function was monitored. Results: Group T demonstrated superior outcomes compared to Group A. Group T had significantly lower intraoperative blood loss (700 mL vs 1200 mL) and a lower bleeding rate per kilogram of body weight (13.3 mL/kg vs 20.4 mL/kg). Coagulation parameters favored Group T, with higher TEG maximum amplitude (55.91 mm vs 45.88 mm) and lower activated partial thromboplastin time (38.04 seconds vs 41.49 seconds). Neither group experienced acute renal injury or kidney function deficiency during hospitalization. Conclusion: TXA and ANH in a small dose during liver resection stabilize clotting, reduce blood loss by 6% compared to hydroxyethyl starch 130/0.4, and do not affect renal function.

Strong Solvent and Dual Lithium Salts Enable Fast-Charging Lithium-Ion Batteries Operating from -78 to 60 °C.

Current lithium-ion batteries degrade under high rates and low temperatures due to the use of carbonate electrolytes with restricted Li+ conduction and sluggish Li+ desolvation. Herein, a strong solvent with dual lithium salts surmounts the thermodynamic limitations by regulating interactions among Li+ ions, anions, and solvents at the molecular level. Highly dissociated lithium bis(fluorosulfonyl)imide (LiFSI) in dimethyl sulfite (DMS) solvent with a favorable dielectric constant and melting point ensures rapid Li+ conduction while the high affinity between difluoro(oxalato)borate anions (DFOB-) and Li+ ions guarantees smooth Li+ desolvation within a wide temperature range. In the meantime, the ultrathin self-limited electrode/electrolyte interface and the electric double layer induced by DFOB- result in enhanced electrode compatibility. The as-formulated electrolyte enables stable cycles at high currents (41.3 mA cm-2) and a wide temperature range from -78 to 60 °C. The 1 Ah graphite||LiCoO2 (2 mAh cm-2) pouch cell achieves 80% reversible capacity at 2 C rate under -20 °C and 86% reversible capacity at 0.1 C rate under -50 °C. This work sheds new light on the electrolyte design with strong solvent and dual lithium salts and further facilitates the development of high-performance lithium-ion batteries operating under extreme conditions.

Mechano-Electrochemically Promoting Lithium Atom Diffusion and Relieving Accumulative Stress for Deep-Cycling Lithium Metal Anodes.

Lithium metal batteries (LMBs) can double the energy density of lithium-ion batteries. However, the notorious lithium dendrite growth and large volume change are not well addressed, especially under deep cycling. Here, an in-situ mechanical-electrochemical coupling system is built, and it is found that tensile stress can induce smooth lithium deposition. Density functional theory (DFT) calculation and finite element method (FEM) simulation confirm that the lithium atom diffusion energy barrier can be reduced when the lithium foils are under tensile strain. Then tensile stress is incorporated into lithium metal anodes by designing an adhesive copolymer layer attached to lithium in which the copolymer thinning can yield tensile stress to the lithium foil. Elastic lithium metal anode (ELMA) is further prepared via introducing a 3D elastic conductive polyurethane (CPU) host for the copolymer-lithium bilayer to release accumulated internal stresses and resist volume variation. The ELMA can withstand hundreds of compression-release cycles under 10% strain. LMBs paired with ELMA and LiNi0.8 Co0.1 Mn0.1 O2 (NCM811) cathode can operate beyond 250 cycles with 80% capacity retention under practical condition of 4 mAh cm-2 cathode capacity, 2.86 g Ah-1 electrolyte-to-capacity ratio (E/C) and 1.8 negative-to-cathode capacity ratio (N/P), five times of the lifetime using lithium foils.

Designing a Quasi-Liquid Alloy Interface for Solid Na-Ion Battery.

Solid-state sodium-ion batteries are attracting great attention due to their high energy density and high safety. However, the Na dendrite growth and poor wettability between sodium and electrolytes seriously limit its application. Herein, we designed a stable and dendrite-suppressed quasi-liquid alloy interface (C@Na-K) for solid sodium-ion batteries (SSIBs). The batteries exhibit excellent electrochemical performance thanks to better wettability and accelerated charge transfer and nucleation mode shifts. The thickness of the liquid phase alloy interface fluctuates along with the exotherm of the cell cycling process, which leads to better rate performance. The symmetrical cell can cycle steadily over 3500 h at 0.1 mA/cm2 at room temperature, and the critical current density can reach 2.6 mA/cm2 at 40 °C. The full cells with the quasi-liquid alloy interface also show outstanding performance; the capacity retention can reach 97.1%, and the average Coulombic efficiency can reach 99.6% of the battery at 0.5 C even after 300 cycles. These results proved the feasibility of using a liquid alloy interface of the anode for high-energy SSIBs, and this innovative approach to stabilizing the interface performance could serve as a basis for the development of next-generation high-energy SSIBs.

A Molecularly Engineered Cathode Lithium Compensation Agent for High Energy Density Batteries.

Prelithiating cathode is considered as one of the most promising lithium compensation strategies for practical high energy density batteries. Whereas most of reported cathode lithium compensation agents are deficient owing to their poor air-stability, residual insulating solid, or formidable Li-extracting barrier. Here, this work proposes molecularly engineered 4-Fluoro-1,2-dihydroxybenzene Li salt (LiDF) with high specific capacity (382.7 mAh g-1 ) and appropriate delithiation potential (3.6-4.2 V) as an air-stable cathode Li compensation agent. More importantly, the charged residue 4-Fluoro-1,2-benzoquinone (BQF) can synergistically work as an electrode/electrolyte interface forming additive to build uniform and robust LiF-riched cathode/anode electrolyte interfaces (CEI/SEI). Consequently, less Li loss and retrained electrolyte decomposition are achieved. With 2 wt% 4-Fluoro-1,2-dihydroxybenzene Li salt initially blended within the cathode, 1.3 Ah pouch cells with NCM (Ni92) cathode and SiO/C (550 mAh g-1 ) anode can keep 91% capacity retention after 350 cycles at 1 C rate. Moreover, the anode free of NCM622+LiDF||Cu cell achieves 78% capacity retention after 100 cycles with the addition of 15 wt% LiDF. This work provides a feasible sight for the rational designing Li compensation agent at molecular level to realize high energy density batteries.

Lithium Foam for Deep Cycling Lithium Metal Batteries.

Li metal anode has been recognized as the most promising anode for its high theoretical capacity and low reduction potential. But its large-scale commercialization is hampered because of the infinite volume expansion, severe side reactions, and uncontrollable dendrite formation. Herein, the self-supporting porous lithium foam anode is obtained by a melt foaming method. The adjustable interpenetrating pore structure and dense Li3 N protective layer coating on the inner surface enable the lithium foam anode with great tolerance to electrode volume variation, parasitic reaction, and dendritic growth during cycling. Full cell using high areal capacity (4.0 mAh cm-2 ) LiNi0.8Co0.1Mn0.1 (NCM811) cathode with the N/P ratio of 2 and E/C ratio of 3 g Ah-1 can stably operate for 200 times with 80% capacity retention. The corresponding pouch cell has <3% pressure fluctuation per cycle and almost zero pressure accumulation.

A Stress Self-Adaptive Structure to Suppress the Chemo-mechanical Degradation for High Rate and Ultralong Cycle Life Sodium Ion Batteries.

Transition-metal phosphides (TMPs) as typical conversion-type anode materials demonstrate extraordinary theoretical charge storage capacity for sodium ion batteries, but the unavoidable volume expansion and irreversible capacity loss upon cycling represent their long-standing limitations. Herein we report a stress self-adaptive structure with ultrafine FeP nanodots embedded in dense carbon microplates skeleton (FeP@CMS) via the spatial confinement of carbon quantum dots (CQDs). Such an architecture delivers a record high specific capacity (778 mAh g-1 at 0.05 A g-1 ) and ultra-long cycle stability (87.6 % capacity retention after 10 000 cycles at 20 A g-1 ), which outperform the state-of-the-art literature. We decode the fundamental reasons for this unprecedented performance, that such an architecture allows the spontaneous stress transfer from FeP nanodots to the surrounding carbon matrix, thus overcomes the intrinsic chemo-mechanical degradation of metal phosphides.

Artificial porous heterogeneous interface for all-solid-state sodium ion battery.

Solid sodium-ion batteries are regarded as promising candidates for next-generation energy storage systems with high energy density and good safety. However, the large interface resistance and dendrite growth between sodium and solid electrolytes, especially at high current densities, severely limits their development. Herein, an artificial porous heterogeneous interface is constructed between sodium and the NASICON electrolyte Na3Hf2Si2PO12 (NHSP). This indicated that the porous heterogeneous interface with high-efficiency ion-electron transfer properties could effectively reduce the interface resistance, inhibit dendrites, and realize good rate performance. The symmetric cell with porous heterogeneous interface could cycle stably for more than 2000 h at 0.2 mA cm-2 at room temperature, and the critical current density reached 2.7 mA cm-2. Our study provides a promising direction for creating a stable interface that meets both the long-cycle and high-rate requirements for all-solid-state sodium-ion batteries.

Data-driven design of high-performance MASnxPb1-xI3 perovskite materials by machine learning and experimental realization.

The photovoltaic performance of perovskite solar cell is determined by multiple interrelated factors, such as perovskite compositions, electronic properties of each transport layer and fabrication parameters, which makes it rather challenging for optimization of device performances and discovery of underlying mechanisms. Here, we propose and realize a novel machine learning approach based on forward-reverse framework to establish the relationship between key parameters and photovoltaic performance in high-profile MASnxPb1-xI3 perovskite materials. The proposed method establishes the asymmetrically bowing relationship between band gap and Sn composition, which is precisely verified by our experiments. Based on the analysis of structural evolution and SHAP library, the rapid-change region and low-bandgap plateau region for small and large Sn composition are explained, respectively. By establishing the models for photovoltaic parameters of working photovoltaic devices, the deviation of short-circuit current and open-circuit voltage with band gap in defective-zone and low-bandgap-plateau regions from Shockley-Queisser theory is captured by our models, and the former is due to the deep-level traps formed by crystallographic distortion and the latter is due to the enhanced susceptibility by increased Sn4+ content. The more difficulty for hole extraction than electron is also concluded in the models and the prediction curve of power conversion efficiency is in a good agreement with Shockley-Queisser limit. With the help of search and optimization algorithms, an optimized Sn:Pb composition ratio near 0.6 is finally obtained for high-performance perovskite solar cells, then verified by our experiments. Our constructive method could also be applicable to other material optimization and efficient device development.

Spontaneous and Selective Potassium Transport through a Suspended Tailor-Cut Ti3C2Tx MXene Film.

Biological ion pumps selectively transport target ions against the concentration gradient, a process that is crucial to maintaining the out-of-equilibrium states of cells. Building an ion pump with ion selectivity has been challenging. Here we show that a Ti3C2Tx MXene film suspended in air with a trapezoidal shape spontaneously pumps K+ ions from the base end to the tip end and exhibits a K+/Na+ selectivity of 4. Such a phenomenon is attributed to a range of properties of MXene. Thanks to the high stability of MXene in water and the dynamic equilibrium between evaporation and swelling, the film keeps a narrow interlayer spacing of ∼0.3 nm when its two ends are connected to reservoirs. Because of the polar electrical structure and hydrophilicity of the MXene nanosheet, K+ ions experience a low energy barrier of ∼4.6 kBT when entering these narrow interlayer spacings. Through quantitative simulations and consistent experimental results, we further show that the narrow spacings exhibit a higher energy barrier to Na+, resulting in K+/Na+ selectivity. Finally, we show that the spontaneous ion transport is driven by the asymmetric evaporation of the interlayer water across the film, a mechanism that is similar to pressure driven streaming current. This work shows how ion transport properties can be facilely manipulated by tuning the macroscopic shape of nanofluidic materials, which may attract interest in the interface of kirigami technologies and nanofluidics and show potential in energy and separation applications.

A Moisture-Assisted Rechargeable Mg-CO2 Battery.

New sustainable energy conversion and storage technologies are required to address the energy crisis and CO2 emission. Among various metal-CO2 batteries that utilize CO2 and offer high energy density, rechargeable Mg-CO2 batteries based on earth-abundant and safe magnesium (Mg) metal have been limited due to the lack of a compatible electrolyte, operation atmosphere, and unambiguous reaction process. Herein, the first rechargeable nonaqueous Mg-CO2 batteries have been proposed with moisture assistance in a CO2 atmosphere. These display more than 250 h cycle life and maintain the discharge voltage over 1 V at 200 mA g-1 . Combining with the experimental observations and theoretical calculations, the reaction in the moisture-assisted Mg-CO2 battery is revealed to be 2 Mg+3 CO2 +6 H2 O↔2 MgCO3 ⋅3 H2 O+C. It is anticipated that the moisture-assisted rechargeable Mg-CO2 batteries would stimulate the development of multivalent metal-CO2 batteries and extend CO2 fixation and utilization for carbon neutrality.

High Energy Density Solid State Lithium Metal Batteries Enabled by Sub-5 µm Solid Polymer Electrolytes.

Solid-state batteries (SSBs) are considered as the most promising next-generation high-energy-density energy storage devices due to their ability in addressing the safety concerns from organic electrolytes and enabling energy dense lithium anodes. To ensure the high energy density of SSBs, solid-state electrolytes (SSEs) are required to be thin and light-weight, and simultaneously offer a wide electrochemical window to pair with high-voltage cathodes. However, the decrease of SSE thickness and delicate structure may increase the cell safety risks, which is detrimental for the practical application of SSBs. Herein, to demonstrate a high-energy-density SSB with sufficient safety insurance, an ultrathin (4.2 µm) bilayer SSE with porous ceramic scaffold and double-layer Li+ -conducting polymer, is proposed. The fire-resistant and stiff ceramic scaffold improves the safety capability and mechanical strength of the composite SSE, and the bilayer polymer structure enhances the compatibility of Li metal anode and high-voltage cathodes. The 3D ceramic facilitates Li-ion conduction and regulates Li deposition. Thus, high energy density of 506 Wh kg-1 and 1514 Wh L-1 is achieved based on LiNi0.8 Co0.1 Mn0.1 O2 (NCM811) cathodes with a low N/P ratio and long lifespan over 3000 h. High-energy-density anode-free cells are further demonstrated.

Redox mediators as charge agents for changing electrochemical reactions.

Redox mediators (RMs) play pivotal roles in enhancing the performance of electrochemical energy storage and conversion systems. Unlike the widely explored areas of electrode materials, electrolytes, separators, and electrolyte additives, RMs have received little attention. This review provides a comprehensive discussion toward understanding the effects of RMs on electrochemical systems, underlying redox mechanisms, and reaction kinetics both experimentally and theoretically. Our discussion focuses on the roles of RMs in various electrochemical systems such as lithium-ion batteries, Li-O2 batteries, Li-S batteries, decoupling electrolysis, supercapacitors, and microbial fuel cells. Depending on the reaction regions where the RMs become active, we can classify them into bulk, solid-solid interfacial, solid-liquid interfacial, and cell-unit RMs. The prospect of developing RMs with effective charge transfer properties along with minimal side-effects is an exciting research direction. Moreover, the introduction of an efficient RM into an electrochemical system can fundamentally change its chemistry; in particular, the electrode reaction polarization can be considerably decreased. In this context, we discuss the key properties of RMs applied for various purposes, and the main issues are addressed.

The Features and Progress of Electrolyte for Potassium Ion Batteries.

Nowadays, Li-ion batteries have achieved great success and are widely used in various fields. However, the scarcity and uneven distribution of lithium resources together with the increasing cost may hamper the sustainable development of Li-ion batteries in the future. Hence, many researchers have turned to potassium ion batteries due to their abundant raw materials, low price, and high energy density. Although great progress has been made in recent years, there are still existing many challenges, especially the severe side reaction between electrolyte and K metal, which leads to an unstable solid-liquid interface and low coulombic efficiency. Hence, an excellent electrolyte may be the key to development of K-ion batteries in the future. Unfortunately, no systematic research has been conducted to study the electrolyte and its role on the performance yet. In order to compensate for this limitation, in this paper, the status and progress of electrolytes for K-ion batteries are reviewed, the issues and challenges existing in the development of electrolyte are clarified, and the future development is prospected.

Reversible Photodriven Droplet Motion on Ti3C2 MXene Film for Diverse Liquids.

The manipulation of liquid droplets on a specific surface with reversible wettability is of great importance for various applications from science to industry. Herein, the concept of a smart, flexible photodriven droplet motion (PDM) device with programmable wettability is designed using the 2D material of MXene film. Because of the MXene photothermal property, the Vaseline layer in the device is in transition between solid and liquid states under the heat transformation due to light illumination, thus attractively producing a reversible wettability for liquid motion with respect to sliding and pinning. Multifarious pathways for liquid motion could be designed through the flexibility of light illumination, which is a revolutionary enhancement in diverse liquid motion to form the desired pathways. In addition, we demonstrated liquid motion under illumination of the back face, which has a profound influence on applications, such as microfluidic systems, microengines, and liquid manipulation.

Long Cycling Life Solid-State Li Metal Batteries with Stress Self-Adapted Li/Garnet Interface.

Inorganic solid-state electrolyte (SSE) has offered a promising option for the safe rechargeable Li metal batteries. However, the solid-solid interfacial incompatibility greatly hampers the practical use. The interface becomes even worse during repeated Li plating/stripping, especially under high current density and long cycling operation. To promise an intimate contact and uniform Li deposition during cycling, we herein demonstrate a stress self-adapted Li/Garnet interface by integrating Li foil with a hyperelastic substrate. Consecutive and conformal physical contact was ensured at Li/Garnet interface during Li plating/stripping, therefore dissipating the localized stress, suppressing Li dendrite formation, and preventing Garnet cracks. Record long cycling life over 5000 cycles was achieved with the ultrasmall hysteresis of 55 mV at high current density of 0.2 mA cm-2. Our strategy provides a new way to stabilize Li/Garnet interface from the perspective of anode mechanical regulation and paves the way for the next generation solid-state Li metal batteries.

Enabling Mg metal anodes rechargeable in conventional electrolytes by fast ionic transport interphase.

Rechargeable magnesium batteries have received extensive attention as the Mg anodes possess twice the volumetric capacity of their lithium counterparts and are dendrite-free. However, Mg anodes suffer from surface passivation film in most glyme-based conventional electrolytes, leading to irreversible plating/stripping behavior of Mg. Here we report a facile and safe method to obtain a modified Mg metal anode with a Sn-based artificial layer via ion-exchange and alloying reactions. In the artificial coating layer, Mg2Sn alloy composites offer a channel for fast ion transport and insulating MgCl2/SnCl2 bestows the necessary potential gradient to prevent deposition on the surface. Significant improved ion conductivity of the solid electrolyte interfaces and decreased overpotential of Mg symmetric cells in Mg(TFSI)2/DME electrolyte are obtained. The coated Mg anodes can sustain a stable plating/stripping process over 4000 cycles at a high current density of 6 mA cm-2. This finding provides an avenue to facilitate fast ion diffusion kinetics of Mg metal anodes in conventional electrolytes.

Revisiting the Electroplating Process for Lithium-Metal Anodes for Lithium-Metal Batteries.

Electroplating has been studied for centuries, not only in the laboratory but also in industry for machinery, electronics, automobile, aviation, and other fields. The lithium-metal anode is the Holy Grail electrode because of its high energy density. But the recyclability of lithium-metal batteries remains quite challenging. The essence of both conventional electroplating and lithium plating is the same, reduction of metal cations. Thus, industrial electroplating knowledge can be applied to revisit the electroplating process for lithium-metal anodes. In conventional electroplating, some strategies like using additives, modifying substrates, applying pulse current, and agitating electrolyte have been explored to suppress dendrite growth. These methods are also effective in lithium-metal anodes. Inspired by that, we revisit the fundamental electroplating theory for lithium-metal anodes in this Minireview, mainly drawing attention to the theory of electroplating thermodynamics and kinetics. Analysis of essential differences between traditional electroplating and plating/stripping of lithium-metal anodes is also presented. Thus, industrial electroplating knowledge can be applied to the electroplating process of lithium-metal anodes to improve commercial lithium-metal batteries and the study of lithium plating/stripping can further enrich the classical electroplating technique.

Ambient oxidation of Ti3C2 MXene initialized by atomic defects.

MXenes are a group of two-dimensional transition metal carbides/nitrides that have been widely used for many useful applications such as energy storage, catalysis and sensors. For large scale applications of MXenes, the ambient stability is a critical issue. However, the detailed degradation mechanism of MXenes remains largely unclear. Here, the oxidation mechanism of MXene flakes under ambient conditions has been studied using aberration corrected scanning transmission electron microscopy (STEM). The heterogeneous growth of titanium oxide has been observed in the vicinity of atomic defects on the MXene basal plane as well as on the edges of MXene flakes. C atoms are oxidized at Ti-vacancies to form amorphous carbon aggregations, while Ti cations are oxidized at the nearby sites with atomic steps/edges. The diffusion of both electrons and Ti cations is involved and the Ti-ion diffusion is prompted by an internal electric field intrinsically built up during oxidation. The anatase TiO2 nanoparticles preferentially grow along the {101} lattice plane. A loose orientation relationship between the anatase TiO2 and MXene was identified, showing that mostly the {101} plane of TiO2 nanocrystals is perpendicular to the Ti3C2-MXene {0001} basal plane. This work reveals at atomic resolution the oxidation mechanism of MXenes under ambient conditions and will shed light on the design and synthesis of more stable MXenes. It may also provide insights to develop a one-step method to synthesize hybrid structures of carbon supported TiO2 nanoparticles for future large scale applications.