Sodium citrate as a self-sacrificial sodium compensation additive for sodium-ion batteries

Practical Evaluation of Presodiation Techniques for High Energy Sodium-Based Batteries

Low-cost rechargeable sodium-based batteries are regarded as ideal alternatives to replace or complement current lithium-ion batteries in large-scale energy storage applications. Unfortunately, the commercial implementation of sodium-based batteries is restricted by their unsatisfied energy density, severe initial capacity decay, and discontented cycle life. Presodiation techniques including anode pretreatment and cathode additives are widely suggested to alleviate the above problems by providing an extra sodium resource to compensate for the initial capacity loss. However, none of them have been applied at the industrial level due to poor kinetics and severe gas evolution. Hence, in this timely review, we reclassify the presodiation techniques based on their operating locations and charge compensation mechanisms, which could provide intuitive perspectives for practical assessment. Key evaluation factors including kinetic performance, gas evolution behavior, environmental stability, and cost are proposed and systematically analyzed. The corresponding optimization strategies and potential applications are provided, followed by the scientific and technical challenges and suggestions for future industrialization. We believe this review will promote the industrial development of presodiation techniques in the future.

Reversible Na15Sn4 alloy compensation for hard carbon anodes to enhance the initial coulombic efficiency in sodium-ion full cells

An effective sodium compensation strategy employs a Na15Sn4 alloy as a dynamic sodium reservoir paired with hard carbon (HC) anodes, undergoing reversible dealloying at low potentials (<0.5 V vs. Na+/Na) to release active Na ions, thereby compensating for irreversible sodium losses during the initial cycles. The full-cell configurations with NaSn@HC in the Na3V2(PO4)3 cathode system achieve an ICE of 90.1%, outperforming conventional hard carbon anodes by more than 50%.

Presodiation technology: progress, strategy and prospects of sacrificial cathode additives in sodium-based energy storage systems

Presodiation technology plays a pivotal role in enhancing the reversible cycle capacity and initial coulomb efficiency (ICE) of sodium-based energy storage systems (SESSs) by pre-supplementing active sodium ions in the electrode materials, which is crucial for the practical application of SESSs. This technology encompasses various methods, including direct contact presodiation (DC), electrochemical presodiation (EC), chemical presodiation, sodium-rich cathode materials presodiation and sacrificial cathode additive (SCA) presodiation. However, the first four methods encounter specific challenges such as safety concerns, complex procedures, high costs or low irreversible capacity, which significantly impede their industrialization progress. In contrast, the SCA method distinguishes itself with its enhanced safety, straightforward operation, low cost, and superior irreversible specific capacity. More importantly, this method demonstrates excellent compatibility with existing methods of constructing SESS, delivering significant potential for industrialization. Herein, this review summarizes the latest research advancements in SCA presodiation technology, with a particular emphasis on optimizing strategies for some close "ideal" SCA enhancement. The aim of this review is to deepen the understanding of SCA presodiation technology and to offer guidance for the commercial application of high energy density SESSs.

Molecular Engineering Strategies for Organic Pre-Sodiation: Progress and Challenges

Pre-sodiation, which is capable of supplying additional active sodium sources to sodium-ion batteries (SIBs), has been widely accepted as one of the most promising approaches to address the issue of active sodium loss during initial charging and subsequent cycling. Organic materials, with their design flexibility and abundant sources, are well-suited for large-scale applications. To achieve effective organic pre-sodiation, precise control over reaction potential is essential. In view of this, molecular engineering strategies are developed to mediate the pre-sodiation potential of organic materials for efficient pre-sodiation. Nevertheless, a comprehensive review of molecular engineering in organic pre-sodiation is still lacking. This timely review aims to present the crucial role of molecular engineering in organic pre-sodiation and provide an up-to-date overview of this field. After the showcasing of fundamental details of molecular engineering in organic pre-sodiation, recent advances in modifying oxidation decomposition/reduction potentials of organic pre-sodiation materials are briefly introduced, with a focus on the structure-activity relationship between functional group modifications and pre-sodiation potential. Future challenges and directions for developing next-generation organic pre-sodiation technologies are also reviewed. The current review provides important insights into molecular engineering in organic pre-sodiation, guiding the development of next-generation technologies of SIBs.

Rational Design of Aqueous Na Ion Batteries Toward High Energy Density and Long Cycle Life

Prussian blue analogues (PBAs) are promising cathode candidates for aqueous Na ion batteries (ANIBs) considering their low-carbon and cost-effective features. However, it is still a huge challenge to achieve desirable energy density coupled with long cycle life due to inherent Na defects in PBAs and the unstable solid-electrolyte interphase (SEI) layer. Herein, we design Na2C4O4 additives as sodium supplements to compensate for Na defects in PBAs, while utilizing the CO2 products decomposed from Na2C4O4 to construct a robust SEI layer containing Na2CO3 species. As proof of concept, our building of full ANIBs using iron-based PBAs and NaTi2(PO4)3 anode with an appropriate amount of Na2C4O4 enable a reversible capacity of ∼144 mA h g-1 at 0.2 C and an excellent cycling stability of 15,000 cycles with 85% retention at 10 C. The proposed concept is further extended to the manganese-based PBA ANIBs to deliver an energy density of 92 W h kg-1 with improved cycling stability.

Carbonyl Chemistry for Advanced Electrochemical Energy Storage Systems

On the basis of the sustainable concept, organic compounds and carbon materials both mainly composed of light C element have been regarded as powerful candidates for advanced electrochemical energy storage (EES) systems, due to theie merits of low cost, eco-friendliness, renewability, and structural versatility. It is investigated that the carbonyl functionality as the most common constituent part serves a crucial role, which manifests respective different mechanisms in the various aspects of EES systems. Notably, a systematical review about the concept and progress for carbonyl chemistry is beneficial for ensuring in-depth comprehending of carbonyl functionality. Hence, a comprehensive review about carbonyl chemistry has been summarized based on state-of-the-art developments. Moreover, the working principles and fundamental properties of the carbonyl unit have been discussed, which has been generalized in three aspects, including redox activity, the interaction effect, and compensation characteristic. Meanwhile, the pivotal characterization technologies have also been illustrated for purposefully studying the related structure, redox mechanism, and electrochemical performance to profitably understand the carbonyl chemistry. Finally, the current challenges and promising directions are concluded, aiming to afford significant guidance for the optimal utilization of carbonyl moiety and propel practicality in EES systems.

Boosting Sodium Compensation Efficiency via a CNT/MnO2 Catalyst toward High-Performance Na-Ion Batteries

The formation of a solid electrolyte interphase on carbon anodes causes irreversible loss of Na+ ions, significantly compromising the energy density of Na-ion full cells. Sodium compensation additives can effectively address the irreversible sodium loss but suffer from high decomposition voltage induced by low electrochemical activity. Herein, we propose a universal electrocatalytic sodium compensation strategy by introducing a carbon nanotube (CNT)/MnO2 catalyst to realize full utilization of sodium compensation additives at a much-reduced decomposition voltage. The well-organized CNT/MnO2 composite with high catalytic activity, good electronic conductivity, and abundant reaction sites enables sodium compensation additives to decompose at significantly reduced voltages (from 4.40 to 3.90 V vs Na+/Na for sodium oxalate, 3.88 V for sodium carbonate, and even 3.80 V for sodium citrate). As a result, sodium oxalate as the optimal additive achieves a specific capacity of 394 mAh g-1, almost reaching its theoretical capacity in the first charge, increasing the energy density of the Na-ion full cell from 111 to 158 Wh kg-1 with improved cycle stability and rate capability. This work offers a valuable approach to enhance sodium compensation efficiency, promising high-performance energy storage devices in the future.

Long-Life Zn Anode Enabled with Complexing Ability of a Benign Electrolyte Additive

The development of aqueous zinc ion batteries (AZIBs) is hindered by several problems, including Zn dendrite/corrosion, side reactions, and hydrogen evolution reaction (HER). Herein, trisodium citrate (NaCit) additive is introduced into the ZnSO4 electrolyte to guide the preferred Zn(002) crystal plane growth, while the Cit- is preferentially adsorbed on the active sites to suppress the HER and Zn corrosion, thus achieving uniform Zn deposition without dendrites. The stable cycle life can reach 2000 h at 0.25 mA cm-2/0.05 mAh cm-2. The density functional theory simulations further indicate that the parallely placed Cit- has the lowest adsorption energy (-6.617 eV); it can form a weak interaction with Zn metal to promote the growth of (002) crystal planes. Furthermore, the assembled Zn//polyaniline full cell and pouch cell both exhibit good rate performance and long cycling stability. The complexation and dissolubilization effects of the NaCit additive provide a means for designing high-performance AZIBs.

Analysis of factors related to thrombosis in patients with PICC placements

This study aimed to investigate the conditions of patients with peripherally inserted central catheter (PICC) placements, analyze the risk factors influencing thrombosis in PICC-placed patients, and formulate more accurate and effective PICC management strategies. A total of 147 patients undergoing PICC placements were selected as the study subjects. Clinical data were collected, and the patients were divided into thrombosis and non-thrombosis groups. Detect levels of bilirubin, white blood cells, venous pressure, heparin concentration, blood flow, citric acid, and platelets. Pearson chi-square test, Spearman correlation analysis, as well as univariate and multivariate logistic regression were employed to analyze independent risk factors. Among the 147 patients with PICC placements, there were 84 males and 63 females. Thrombosis occurred in 116 cases, with an incidence rate of 78.91%. Pearson chi-square test showed a significant correlation between citric acid, blood flow, platelets and frailty (P < .001) with thrombosis formation. Spearman correlation analysis revealed a significant correlation between citric acid (ρ = -0.636, P < .001), blood flow (ρ = 0.584, P < .001), platelet count (ρ = 0.440, P < .001), frailty (ρ = -0.809, P < .001) and thrombosis in PICC placement patients. Univariate logistic regression analysis indicated a significant correlation between thrombosis formation and citric acid (OR = 0.022, 95% CI = 0.006-0.08, P < .001), blood flow (OR = 33.973, 95% CI = 9.538-121.005, P < .001), platelet count (OR = 22.065, 95% CI = 5.021-96.970, P < .001), frailty (OR = 0.003, 95% CI = 0.001-0.025, P < .001). Multivariate logistic regression analysis also showed a significant correlation between thrombosis formation and citric acid (OR = 0.013, 95% CI = 0.002-0.086, P < .001), blood flow (OR = 35.064, 95% CI = 6.385-192.561, P < .001), platelet count (OR = 4.667, 95% CI = 0.902-24.143, P < .001), frailty (OR = 0.006, 95% CI = 0.001-0.051, P < .001). However, gender (OR = 0.544, 95% CI = 0.113-2.612, P = .447), age (OR = 4.178, 95% CI = 0.859-20.317, P = .076), bilirubin (OR = 2.594, 95% CI = 0.586-11.482, P = .209), white blood cells (OR = 0.573, 95% CI = 0.108-3.029, P = .512), venous pressure (OR = 0.559, 95% CI = 0.129-2.429, P = .438), and heparin concentration (OR = 2.660, 95% CI = 0.333-21.264, P = .356) showed no significant correlation with thrombosis formation. Patients with PICC placements have a higher risk of thrombosis, citric acid, blood flow, platelet count and frailty are the main risk factors.

Controllable synthesis of a Na-enriched Na4V2(PO4)3 cathode for high-energy sodium-ion batteries: a redox-potential-matched chemical sodiation approach

Exploring a sodium-enriched cathode (i.e. Na4V2(PO4)3, which differs from its traditional stoichiometric counterpart Na3V2(PO4)3 that can provide extra endogenous sodium reserves to mitigate the irreversible capacity loss of the anode material (i.e. hard carbon), is an intriguing presodiation method for the development of high energy sodium-ion batteries. To meet this challenge, herein, we first propose a redox-potential-matched chemical sodiation approach, utilizing phenazine-sodium (PNZ-Na) as the optimal reagent to sodiate the Na3V2(PO4)3 precursor into Na-enriched Na4V2(PO4)3. The spontaneous sodiation reaction enables a fast reduction of one-half V ions from V3+ to V2+, followed by the insertion of one Na+ ion into the NASICON framework, which only takes 90 s to obtain the phase-pure Na4V2(PO4)3 product. When paired with a hard carbon anode, the resulting Na4VP‖HC full cell exhibits a high energy density of 251 W h kg-1, which is 58% higher than that of 159 W h kg-1 for the Na3VP‖HC control cell. Our chemical sodiation methodology provides an innovative approach for designing sodium-rich cathode materials and could serve as an impetus to the development of advanced sodium-ion batteries.

High-Efficiency Separator Capacity-Compensation Strategy Applied to Sodium-Ion Batteries

Sodium-ion batteries (SIBs) are expected to replace partial reliance on lithium-ion batteries (LIBs) in the field of large-scale energy storage as well as low-speed electric vehicles due to the abundance, wide distribution, and easy availability of sodium metal. Unfortunately, a certain amount of sodium ions are irreversibly trapped in the solid electrolyte interface (SEI) layer during the initial charging process, causing the initial capacity loss (ICL) of the SIBs. A separator capacity-compensation strategy is proposed, where the capacity compensator on the separator oxidizes below the high cut-off voltage of the cathode to provide additional sodium ions. This strategy shows attractive advantages, including adaptability to current production processes, no impairment of cell long-cycle life, controlled pre-sodiation degree, and strategy universality. The separator capacity-compensation strategy is applied in the NaNi1/3 Fe1/3 Mn1/3 O2 (NMFO)||HC full cell and achieve a compensated capacity ratio of 18.2%. In the Na3 V2 (PO4 )3 (NVP)||HC full cell, the initial reversible specific capacity is increased from 61.0 mAh g-1 to 83.1 mAh g-1 . The separator capacity-compensation strategy is proven to be universal and provides a new perspective to enhance the energy density of SIBs.

Enhancing the Initial Coulombic Efficiency of Sodium-Ion Batteries via Highly Active Na2 S as Presodiation Additive

Recently, sodium-ion batteries (SIBs) have received considerable attention for large-scale energy storage applications. However, the low initial Coulombic efficiency of traditional SIBs severely impedes their further development. Here, a highly active Na2 S-based composite is employed as a self-sacrificial additive for sodium compensation in SIBs. The in situ synthesized Na2 S is wrapped in a carbon matrix with nanoscale particle size and good electrical conductivity, which helps it to achieve a significantly enhanced electrochemical activity as compare to commercial Na2 S. As a highly efficient presodiation additive, the proposed Na2 S/C composite can reach an initial charge capacity of 407 mAh g-1 . When 10 wt.% Na2 S/C additive is dispersed in the Na3 V2 (PO4 )3 cathode, and combined with a hard carbon anode, the full cell achieves 24.3% higher first discharge capacity, which corresponds to a 18.3% increase in the energy density from 117.2 to 138.6 Wh kg-1 . Meanwhile, it is found that the Na2 S additive does not generate additional gas during the initial charging process, and under an appropriate content, its reaction product has no adverse impact on the cycling stability and rate performance of SIBs. Overall, this work establishes Na2 S as a highly effective additive for the construction of advanced high-energy-density SIBs.

Significantly Improving the Initial Coulombic Efficiency of TiO2 Anode for Sodium-Ion Batteries

Titanium dioxide (TiO2) can serve as a candidate anode material for sodium-ion batteries (SIBs) with the merits of their low cost, abundance, and environment friendliness. However, its low initial Coulombic efficiency (ICE) and sluggish sodium-ion diffusion greatly limit its further practical applications. Herein, we report a one-step prepotassiation strategy to modify commercial TiO2 by a spontaneous chemical reaction using potassium naphthalene (K-Nt). Prepotassiation effectively compensates for the irreversible Na loss and induces a homogeneous, dense, and robust artificial solid electrolyte interphase (SEI) on its surface. The well-distributed artificial SEI suppresses the excessive electrolyte decomposition, contributing to rapid interfacial kinetics and stable Na+ insertion/extraction. Therefore, such modified commercial TiO2 anodes demonstrate significantly improved ICE (72.4%) and outstanding rate performance (176.4 mAh g-1 at 5 A g-1). This simple and efficient method for promoting ICEs and interfacial chemistry also demonstrates universality and practical value for other anodes in SIBs.

Artificial Organo-Fluoro-Rich Anode Electrolyte Interface and Partially Sodiated Hard Carbon Anode for Improved Cycle Life and Practical Sodium-Ion Batteries

In this work, a strategy is introduced wherein without keeping any excess cathode, a practical full-cell sodium-ion battery has been demonstrated by utilizing a hard carbon (HC) anode and sodium vanadium fluorophosphate and carbon nanotube composite (NVPF@C@CNT) cathode. A thin, robust, and durable solid electrolyte interface (SEI) is created on the surface of HC through its incubation wetted with a fluoroethylene carbonate (FEC)-rich warm electrolyte in direct contact with Na metal. During the incubation, the HC anode is partially sodiated and passivated with a thin SEI layer. The sodium-ion full cell fabricated while maintaining N/P ∼1.1 showed the first cycle Coulombic efficiency of ∼97% and delivered a stable areal capacity of 1.4 mAh cm^-2 at a current rate of 0.1 mA cm^-2 realized for the first time to the best of our knowledge. The full cell also showed a good rate capability, retaining 1.18 mAh cm^-2 of its initial capacity even at a high current rate of 0.5 mA cm^-2, and excellent cycling stability, giving a capacity of ∼1.0 mAh cm^-2 after 500 cycles. The current strategy presents a practical way to make a sodium-ion full cell, utilizing no excess cathode material, significantly saving cost and time.

A high-capacity self-sacrificial additive based on electroactive sodiated carbonyl groups for sodium-ion batteries

A new type of high-capacity sacrificial additive (Na₄C₆O₆) is proposed to replenish the sodium loss in sodium ion full-cells. The HC//Na₃V₂(PO₄)₂F₃ full-cells demonstrate significantly enhanced energy density after introducing an appropriate amount of additive.