RESUMEN

Organics are gaining significance as electrode materials due to their merits of multi-electron reaction sites, flexible rearrangeable structures and redox reversibility. However, organics encounter finite electronic conductivity and inferior durability especially in organic electrolytes. To circumvent above barriers, we propose a novel design strategy, constructing conductive network structures with extended π-π superposition effect by manipulating intermolecular interaction. Tetralithium 1,4,5,8-naphthalenetetracarboxylate (LNTC) interwoven by carbon nanotubes (CNTs) forms LNTC@CNTs composite firstly for Li-ion storage, where multiple conjugated carboxyls contribute sufficient Li-ion storage sites, the unique network feature enables electrolyte and charge mobility conveniently combining electron delocalization in π-conjugated system, and the enhanced π-π superposition effect between LNTC and CNTs endows laudable structural robustness. Accordingly, LNTC@CNTs maintain an excellent Li-ion storage capacity retention of 96.4 % after 400 cycles. Electrochemical experiments and theoretical simulations elucidate the fast reaction kinetics and reversible Li-ion storage stability owing to the electron delocalization and π-π superposition effect, while conjugated carboxyls are reversibly rearranged into enolates during charging/discharging. Consequently, a dual-ion battery combining this composite anode and expanded graphite cathode exhibits a peak specific capacity of 122 mAh g-1 and long cycling life with a capacity retention of 84.2 % after 900 cycles.

RESUMEN

Carbonyl or imine-based compounds have received a great deal of attention due to their high specific capacity and designability as cathodes for aqueous rechargeable organo-aluminum batteries. However, the inherent low conductivity and high solubility of carbonyl and imine-based compounds severely affect the cycling stability of aluminum batteries. Therefore, it is urgent to find an organic cathodes material with low solubility and good cycling performance. In this work, dibenzo[a,c]dibenzo[5,6:7,8]quinoxalino[2,3-i]phenazine-10,21-dione (DDQP) were synthesized by simple dehydration condensation to form new imine covalent bonds, which led to the synthesis of imine-conjugated backbone structures with carbonyl, extended π-conjugation planes, and increased active sites, resulting in increased specific capacities. Its storage mechanism with Al(OTF)2+ has also been confirmed. This monovalent ion usually possesses a lower coulombic interaction, which leads to a reduced solubility of DDQP during redox processes and improves its cyclic stability. The specific capacity of DDQP is 252.22 mAh/g at a current density of 400 mA g-1. After cycling, the discharge specific capacity remains at 219 mAh/g. Surprisingly, the conductivity of the battery also is improved by this structure of multiple active sites. And it can be further confirmed by theoretical calculations that the synthesis of DDQP realigns the arrangement of the electron cloud, enhances the electron affinity, and reduces the energy gap. This study provides a new reference for improving the performance of aqueous organic aluminum batteries.

RESUMEN

Alkaline metal-air batteries are advantageous in high voltage, low cost, and high safety. However, metal anodes are heavily eroded in strong alkaline electrolytes, causing serious side reactions including dendrite growth, passivation, and hydrogen evolution. To address this limitation, we successfully synthesized an organic N-heterocycle compound (NHCC) to serve as an alternative anode. This compound not only exhibits remarkable stability but also possesses a low redox potential (-1.04 V vs. Hg/HgO) in alkaline environments. To effectively complement the low redox potential of the NHCC anode, we designed a dual-salt highly concentrated electrolyte (4.0 M KOH+10.0 M KCF3 SO3 ). This electrolyte expands the electrochemical stability window to 2.3 V through the robust interaction between the O atom in H2 O molecule with the K+ of KCF3 SO3 (H-O⋅⋅⋅KCF3 SO3 ). We further demonstrated the K+ uptaken/extraction storage mechanism of NHCC anodes. Consequently, the alkaline aqueous NHCC anode-air batteries delivers a high battery voltage of 1.6 V, high-rate performance (101.9 mAh g-1 at 100 A g-1 ) and long cycle ability (30,000 cycles). Our work offers a molecular engineering strategy for superior organic anode materials and develops a novel double superconcentrated conductive salt electrolyte for the construction of high-rate, long-cycle alkaline aqueous organic anode-air batteries.

RESUMEN

Considering the extensive resources, flexible structural designability, and abundant active sites, organic electrodes have been considered as the ideal sodium storage materials. However, organic materials generally face the limitations of unstable and dissolved characteristic, leading to a poor cyclic stability. In this work, we proposed a carbon nanotube (CNT) modified polyimide as the anode for sodium-based dual-ion battery (SDIB). The polyimide remains well the structure and morphology of monomer with a stable conjugated structure and high degree of crystallinity, effectively enhancing the electrochemical performance of the SDIBs. Also, the cooperation with CNT particularly improves the ion conductivity of the anode and advances the rate performance. Combined with an ionic liquid electrolyte, the constructed dual-ion battery exhibits excellent rate capability, high specific discharge capacity and stable cycling performance. It delivers a specific discharge capacity of 119.3 mA h g-1 at 0.2 C (1 C=100 mA g-1) and still has a specific discharge capacity of 82.3 mA h g-1 even after 1000 cycles at 10 C. Besides, the system displays a low self-discharge rate and stable fast charging performance, which is expected to be applied in the large-scale electrochemical energy storage devices and inspire the future development of SDIBs.

RESUMEN

In this work, we prepared a green, cheap material by chelating humic acid with ferric ions (HA-Fe) and used it as an anode material in LIBs for the first time. From the SEM, TEM, XPS, XRD, and nitrogen adsorption-desorption experimental results, it was found that the ferric ion can chelate with humic acid successfully under mild conditions and can increase the surface area of materials. Taking advantage of the chelation between the ferric ions and HA, the capacity of HA-Fe is 586 mAh·g-1 at 0.1 A·g-1 after 1000 cycles. Moreover, benefitting from the chelation effect, the activation degree of HA-Fe (about 8 times) is seriously improved compared with pure HA material (about 2 times) during the change-discharge process. The capacity retention ratio of HA-Fe is 55.63% when the current density increased from 0.05 A·g-1 to 1 A·g-1, which is higher than that of HA (32.55%) and Fe (24.85%). In the end, the storage mechanism of HA-Fe was investigated with ex-situ XPS measurements, and it was found that the C=O and C=C bonds are the activation sites for storage Li ions but have different redox voltages.

RESUMEN

One of the biggest obstacles to the development of aqueous proton batteries (APBs), despite numerous optimization techniques, is the preparation and use of high-performance electrode materials. In this work, to improve the high solubility, limited capacity and poor cycle life of small organic molecules in APBs, homogeneous dispersed quinone-amine polymer nanospheres (PQANS) (average diameter: 220 nm) were synthesized by a polymerization reaction based on 3,3'-diaminobenzidine (DAB) and benzoquinone (BQ), making them suitable for proton storage in aqueous systems. As an anode for APBs, the obtained PQANS exhibits an improved reversible capacity of 126.2 mAh/g at 1 A/g after 300 cycles. The durable stable measurement of PQANS at 10 A/g was also conducted with a specific capacity of 66.8 mAh/g after 12,000 cycles. A series of in situ or ex situ measurements were used to establish the superior H+ storage mechanism of PQANS. A novel reaction mechanism of redox enhancement was revealed due to the existence of more carbonyl groups after the first cycle. Theoretical calculations were conducted to help illustrate the principle of binding protons with functional groups in PQANS. Finally, a PQANS anode-based aqueous proton full battery was constructed to demonstrate its potential application, which exhibits a specific capacity of 50.6 mAh/g at 1 A/g (600 cycles). This work provides a reference for preparing high-performance polymer-based electrode materials in aqueous batteries.

RESUMEN

Rechargeable sodium-ion batteries (SIBs) have been considered as promising energy storage devices owing to the similar "rocking chair" working mechanism as lithium-ion batteries and abundant and low-cost sodium resource. However, the large ionic radius of the Na-ion (1.07 Å) brings a key scientific challenge, restricting the development of electrode materials for SIBs, and the infeasibility of graphite and silicon in reversible Na-ion storage further promotes the investigation of advanced anode materials. Currently, the key issues facing anode materials include sluggish electrochemical kinetics and a large volume expansion. Despite these challenges, substantial conceptual and experimental progress has been made in the past. Herein, we present a brief review of the recent development of intercalation, conversion, alloying, conversion-alloying, and organic anode materials for SIBs. Starting from the historical research progress of anode electrodes, the detailed Na-ion storage mechanism is analyzed. Various optimization strategies to improve the electrochemical properties of anodes are summarized, including phase state adjustment, defect introduction, molecular engineering, nanostructure design, composite construction, heterostructure synthesis, and heteroatom doping. Furthermore, the associated merits and drawbacks of each class of material are outlined, and the challenges and possible future directions for high-performance anode materials are discussed.

RESUMEN

In this work, two isomers are mixed in different proportions and then alkalized as the organic anode material for sodium-ion batteries (SIBs). The mixed material, denoted as PN, shows distinct morphology and electrochemical properties, compared to the single-component Na-CPP and Na-CPN. The Initial Coulombic Efficiency (ICE) value obtained by using the mixed PN as anode is higher than that using the single component. And the capacity retention rate of the mixed PN electrode is 92% after 1200 cycles under 935 mA g-1 high current density. This is mainly due to the superior morphology of the mixed PN electrode (the optimal ratio is CPP: CPN = 3: 1, the mass ratio (or molar ratio)), which exhibits more uniform spherical particles, thus increasing the contact area with the electrolyte and ensuring close contact with the conductive carbon. As a result, the ICE and cycle performance is improved because of the reduced irreversible side reactions. As far as we know, this is the first example of mixing two isomers as organic anode materials in traditional SIBs, and this strategy may provide new insights into future development of organic electrode materials.

RESUMEN

Bioderived molecules have been identified as viable anodes for organic potassium-ion batteries (OPIBs) due to the abundance of the necessary natural resources, their high capacity, and their sustainability. However, the high solubility and the inherent nonconductivity cause serious capacity decay and large voltage hysteresis. Here, the biomass molecule juglone was cross-linked with a carbon nanotube network, coupling and cooperating with sodium alginate binder (J@CNT-SA), and was proposed to inhibit small molecule dissolution via weak intermolecular interactions. The synergistic effect of hydrogen bonding and π-π stacking is proven for its outstanding reversible high capacities (262 mA h g-1 at 0.05 A g-1), and a remarkable long life span with capacity retention of 77% over 5000 cycles. Further in situ Fourier transform infrared spectroscopy (FTIR) was performed to reveal the electrochemical mechanism. The feasibility of juglone as an anode for PIBs paves the way for other natural organic small molecules to be investigated as potential energy storage materials.

Asunto(s)

RESUMEN

Covalent organic frameworks (COF) possess a robust and porous crystalline structure, making them an appealing candidate for energy storage. Herein, we report an exfoliated polyimide COF composite (P-COF@SWCNT) prepared by an in situ condensation of anhydride and amine on the single-walled carbon nanotubes as advanced anode for potassium-ion batteries (PIBs). Numerous active sites exposed on the exfoliated frameworks and the various open pathways promote the highly efficient ion diffusion in the P-COF@SWCNT while preventing irreversible dissolution in the electrolyte. During the charging/discharging process, K+ is engaged in the carbonyls of imide group and naphthalene rings through the enolization and π-K+ effect, which is demonstrated by the DFT calculation and XPS, ex-situ FTIR, Raman. As a result, the prepared P-COF@SWCNT anode enables an incredibly high reversible specific capacity of 438 mA h g-1 at 0.05 A g-1 and extended stability. The structural advantage of P-COF@SWCNT enables more insights into the design and versatility of COF as an electrode.

RESUMEN

Due to the large abundance, low redox potential, and multivalent properties of calcium (Ca), Ca-ion batteries (CIBs) show promising prospects for energy storage applications. However, current research on CIBs faces the challenges of unsatisfactory cycling stability and capacity, mainly restricted by the lack of suitable electrolytes and electrode materials. Herein, we firstly developed a 3.5 m concentrated electrolyte with a calcium bis(fluorosulfonyl)imide (Ca(FSI)2 ) salt dissolved in carbonate solvents. This electrolyte significantly improved the intercalation capacity for anions in the graphite cathode and contributed to the reversible insertion of Ca2+ in the organic anode. By combining this concentrated electrolyte with the low-cost and environmentally friendly graphite cathode and organic anode, the assembled Ca-based dual-ion battery (Ca-DIB) exhibits 75.4 mAh g-1 specific discharge capacity at 100 mA g-1 and 84.7 % capacity retention over 350 cycles, among the best results known for CIBs.

RESUMEN

In the search for novel anode materials for lithium-ion batteries (LIBs), organic electrode materials have recently attracted substantial attention and seem to be the next preferred candidates for use as high-performance anode materials in rechargeable LIBs due to their low cost, high theoretical capacity, structural diversity, environmental friendliness, and facile synthesis. Up to now, the electrochemical properties of numerous organic compounds with different functional groups (carbonyl, azo, sulfur, imine, etc.) have been thoroughly explored as anode materials for LIBs, dividing organic anode materials into four main classes: organic carbonyl compounds, covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and organic compounds with nitrogen-containing groups. In this review, an overview of the recent progress in organic anodes is provided. The electrochemical performances of different organic anode materials are compared, revealing the advantages and disadvantages of each class of organic materials in both research and commercial applications. Afterward, the practical applications of some organic anode materials in full cells of LIBs are provided. Finally, some techniques to address significant issues, such as poor electronic conductivity, low discharge voltage, and undesired dissolution of active organic anode material into typical organic electrolytes, are discussed. This paper will guide the study of more efficient organic compounds that can be employed as high-performance anode materials in LIBs.

RESUMEN

Sodium-ion batteries are commanding increasing attention owing to their promising electrochemical performance and sustainability. Organic electrode materials (OEMs) complement such technologies as they can be sourced from biomass and recycling them is environmentally friendly. Organic anodes based on sodium carboxylates have exhibited immense potential, except the limitation of current synthesis methods concerning upscaling and energy costs. In this work, a rapid and energy efficient microwave-assisted synthesis for organic anodes is presented using sodium naphthalene-2,6-dicarboxylate as a model compound. Optimizing the synthesis and electrode composition enables the compound to deliver a reversible initial capacity of ≈250 mAh g-1 at a current density of 25 mA g-1 with a high initial Coulombic efficiency (≈78%). The capacity is stable over 400 cycles and the compound also exhibits good rate performance. The successful demonstration of this rapid synthesis may facilitate the transition to preparing organic battery materials by scalable, efficient methods.

RESUMEN

Combining the advantages of dual-ion batteries (DIBs) and sodium-ion batteries (SIBs), we herein develop a superior sodium-based dual-ion battery (Na-DIB) based on the PTCDA organic anode and ionic liquid (IL) electrolyte. The system shows the highest specific discharge capacity of 177 mAh g-1 at 0.5C and excellent capacity retention over 100% at 2C after 200 cycles. Notably, even at an ultrahigh rate of 20C, the battery still maintains a considerable capacity of 60 mAh g-1 with a coulombic efficiency (CE) close to 100 and 94% capacity retention after 1000 cycles. Moreover, the self-discharge of the system has been investigated and shown to have an extremely low value of 0.18% h-1. Consequently, this work presents an excellent Na-DIB system, which could be a promising candidate for large-scale applications.

RESUMEN

The sodium-ion battery (SIB) has the potential to be the next-generation rechargeable system, utilizing cheap and abundant sodium material. One of the key obstacles to sodium batteries is the lack of efficient and stable anode materials. Compared with traditional inorganic electrode materials, organic materials are more attractive because of their easier sodium transport accessibility and the diversities of organic frameworks and functional groups. In this work, two molecules (Na-CPN and Na-CPP) were synthesized and used as anode materials for SIBs. Structurally, the two compounds are isomers, and they are distinguished by the position of N atoms in phenylpyridine. Na-CPP showed a high reversible capacity of 197 mAh g-1 , and its capacity could maintain 99.1 % of its initial value even after 350 cycles of 100 mA g-1 . Moreover, after going through 1200 cycles at a current density of 5 C, the Na-CPP electrode still retained a capacity rate of 89.9 %. In contrast, Na-CPN exhibited inferior capacity and rate performance because of its larger polarization, particle size, and charge transport resistance.

RESUMEN

Low-molecular-weight carbonyl-containing compounds are considered beneficial energy storage materials in alkali metal-ion/alkaline earth metal-ion secondary batteries owing to the ease of their synthesis, low cost, rapid kinetics, and high theoretical energy density. This study aims to prepare a novel carbonyl compound containing a maleamic acid (MA) backbone as a material with carbon black to a new MA anode electrode for a lithium-ion battery. MA was subjected to attenuated total reflection-Fourier-transform infrared spectroscopy, and its morphology was assessed through scanning electron microscopy, followed by differential scanning calorimetry to determine its thermal stability. Thereafter, the electrochemical properties of MA were investigated in coin cells (2032-type) containing Li metal as a reference electrode. The MA anode electrode delivered a high reversible capacity of about 685 mAh g-1 in the first cycle and a higher rate capability than that of the pristine carbon black electrode. Energy bandgap analysis, electrochemical impedance, and X-ray photoelectron spectroscopy revealed that MA significantly reduces cell impedance by reforming its chemical structure into new nitrogen-based highly ionic diffusion compounds. This combination of a new MA anode electrode with MA and carbon black can increase the performance of the lithium-ion battery, and MA majorly outweighs transitional carbon black.

RESUMEN

Rechargeable batteries are essential elements for many applications, ranging from portable use up to electric vehicles. Among them, lithium-ion batteries have taken an increasing importance in the day life. However, they suffer of several limitations: safety concerns and risks of thermal runaway, cost, and high carbon footprint, starting with the extraction of the transition metals in ores with low metal content. These limitations were the motivation for an intensive research to replace the inorganic electrodes by organic electrodes. Subsequently, the disadvantages that are mentioned above are overcome, but are replaced by new ones, including the solubility of the organic molecules in the electrolytes and lower operational voltage. However, recent progress has been made. The lower voltage, even though it is partly compensated by a larger capacity density, may preclude the use of organic electrodes for electric vehicles, but the very long cycling lives and the fast kinetics reached recently suggest their use in grid storage and regulation, and possibly in hybrid electric vehicles (HEVs). The purpose of this work is to review the different results and strategies that are currently being used to obtain organic electrodes that make them competitive with lithium-ion batteries for such applications.

RESUMEN

Classical organic anode materials for Na-ion batteries are mostly based on conjugated carboxylate compounds, which can stabilize added electrons by the double-bond reformation mechanism. Now, 1,4-cyclohexanedicarboxylic acid (C8 H12 O4 , CHDA) with a non-conjugated ring (-C6 H10 -) connected with carboxylates is shown to undergo electrochemical reactions with two Na ions, delivering a high charge specific capacity of 284 mA h g-1 (249 mA h g-1 after 100 cycles), and good rate performance. First-principles calculations indicate that hydrogen-transfer-mediated orbital conversion from antibonding π* to bonding σ stabilize two added electrons, and reactive intermediate with unpaired electron is suppressed by localization of σ-bonds and steric hindrance. An advantage of CHDA as an anode material is good reversibility and relatively constant voltage. A large variety of organic non-conjugated compounds are predicted to be promising anode materials for sodium-ion batteries.