Desolvation Behavior Research Articles

Boosting de-solvation via halloysite nanotubes-cellulose composite separator for dendrite-free zinc anodes

Aqueous zinc-ion batteries (ZIBs) have attracted considerable attention owing to intrinsic advantages, which encompass inherent safety and a cost-effective manufacturing process. Nevertheless, the lifespan of Zn anodes is limited by inclement dendrite growth and adverse side reactions, impeding the commercial viability of ZIBs. In this study, we engineered a multifunctional cellulose-based separator (HC) synthesized from halloysite nanotubes (HNTs) and cellulose to address these challenges effectively. Leveraging the exceptional water adsorption capacity and the unique inner positive and outer negative tubular structure of HNTs molecules, the HC separator facilitates the de-solvation behavior of [Zn(H2O)6]2+ and promotes uniform deposition of Zn2+. Furthermore, the HC separator demonstrates superior wettability, excellent flexibility, and higher ionic conductivity, which further lead to dendrite-free zinc deposition, a 2700-h cycling lifespan, and a coulombic efficiency (CE) of 98.88 % after 100 cycles. Notably, the ZIBs incorporating the HC separator exhibit exceptional cycling performance, retaining 83.5 % of their capacity after 2000 cycles at 5 A g−1. This novel approach offers a valuable direction for the advancement of cost-effective and durable ZIBs.

Remodeling Highly Fluorinated Electrolyte via Shielding Agent Regulation toward Practical Lithium Metal Batteries.

Highly fluorinated electrolytes have proved effective in improving electrochemical stability of lithium metal batteries. However, excessive fluorination not only detrimentally impacts the electrolyte ionic conductivity, but also inevitably forms the over-fluorinated interphases with sluggish ion diffusivity. Herein, a strategy on remodeling Li+ solvation structure in highly fluorinated electrolyte aided is proposed by fluorinated amide (FDMA), which denoted as "shielding agent". Benefitting from FDMA's high donor number (DN)value (22.1), the Li+-dipole (fluoroethylene carbonate (FEC) or trans-4,5-Difluoroethylenecarbonate (DFEC)) interaction is interrupted and the participation of FDMA in primary solvation sheath fructify the solid-electrolyte interphase without scarifying the privilege of fluorinated electrolyte on interphase chemistry. Eventually, the optimal high-fluorinated electrolyte (FDMA/DFEC + 1.0mol L-1 LiTFSI) with this unique shielding effect displays high ionic conductivity and rapid Li+ desolvation behavior, enabling Li||LiNi0.6Co0.2Mn0.2O2 (Li||NCM622) to achieve an ultralong cycle-life of 2000 cycles at 1C with 84.7% capacity retention. Even under extreme conditions (NCM622: 10mg cm-2; electrolyte: 20µL; Li: 50µm), the Li||NCM622 displays excellent electrochemical performance. Additionally, 447Wh kg-1 Li||LiNi0.8Co0.1Mn0.1O2 (Li||NCM811) pouch cells have been successfully fabricated and demonstrate an exceptional cycle-life over 150 cycles. The proposed "shielding" strategy to modulate the solvation structure paves the way for developing practical LMBs with fluorinated electrolytes.

Recent advances in zinc-ion dehydration strategies for optimized Zn-metal batteries.

Aqueous Zn-metal batteries have attracted increasing interest for large-scale energy storage owing to their outstanding merits in terms of safety, cost and production. However, they constantly suffer from inadequate energy density and poor cycling stability due to the presence of zinc ions in the fully hydrated solvation state. Thus, designing the dehydrated solvation structure of zinc ions can effectively address the current drawbacks of aqueous Zn-metal batteries. In this case, considering the lack of studies focused on strategies for the dehydration of zinc ions, herein, we present a systematic and comprehensive review to deepen the understanding of zinc-ion solvation regulation. Two fundamental design principles of component regulation and pre-desolvation are summarized in terms of solvation environment formation and interfacial desolvation behavior. Subsequently, specific strategy based distinct principles are carefully discussed, including preparation methods, working mechanisms, analysis approaches and performance improvements. Finally, we present a general summary of the issues addressed using zinc-ion dehydration strategies, and four critical aspects to promote zinc-ion solvation regulation are presented as an outlook, involving updating (de)solvation theories, revealing interfacial evolution, enhancing analysis techniques and developing functional materials. We believe that this review will not only stimulate more creativity in optimizing aqueous electrolytes but also provide valuable insights into designing other battery systems.

Boosting tough metal Zn anode by MOF layer for high-performance zinc-ion batteries

Metal-organic frameworks (MOFs) have been used to stabilize the metal zinc anode, yet the developed coating materials ignore the influence of intergranular space on deteriorating Zn electrode. Herein, we propose the channel sizes of MOFs as the key control factor to balance the zinc ion flux and Zn2+ desolvation behavior within the channels and between the intergranular spaces. Among three coating layers made by MOFs, the MOF-5W layer with confined spaces and channels is capable to promote the spontaneous desolvation process. The activated surface sites on MOF-5W endow the intergranular channels with accelerated ion transportation and spontaneous Zn2+ desolvation. Two kinds of migration paths are well-matched, as the MOF-5W@Zn anode shows Zn stripping/plating over 5000 cycles at 40 mA cm‒2, as well as cycling stability of 1050 h with high areal capacity of 10 mAh cm‒2. The findings enlighten the innovative research for tough Zn anode.

How Thick Aqueous Alkali Should be Better for Aluminum-Air Batteries at Sub-Zero Temperatures: A Critical Anti-Freezing Concentration.

The application of portable aluminum-air batteries (AABs) in extreme environments is an inevitable demand for future development. Aqueous electrolytefreezing is a major challenge for low-temperature operations. Conventionally, enlightened by the organic system in metal ion batteries, blindly increasing the concentration is regarded as an efficient technique to reduce the freezing point (FP). However, the underlying contradiction between the adjusting mechanism of the FP and OH- transportation is ignored. Herein, the aqueous alkali solution of CsOH is researched as a prototype to disclose the intrinsic conductive behavior and related solvent structure evolution. Different from these inorganic electrolyte systems, the concept of a critical anti-freezing concentration (CFC) is proposed based on a specific temperature. The relationship between hydrogen bond reconstruction and de-solvation behavior is analyzed. A high conductivity is obtained at -30°C, which is also a recorded value in an intrinsic aqueous AAB. The homogenous dissolution of the Al anode is also observed. As a general rule, the CFC concept is also applied in both the KOH and NaOH systems.

Predicting particle quality attributes of organic crystalline materials using Particle Informatics

In this work, a novel quercetin solvate of dimethylformamide (QDMF) was studied. The crystal structure was solved using single crystal X-ray diffraction and analysed using synthon analysis and other particle informatics tools (e.g., solvate analyser). The thermal behaviour and thermodynamic stability of QDMF were studied experimentally using Raman spectroscopy, ATR-FTIR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. A clear relationship between the two-step desolvation behaviour of QDMF and the type, strength, and directionality of the main bulk synthons characterizing the QDMF structure was observed. Additionally, the attachment energy model was used to predict the QDMF morphology, together with facet-specific topology and chemical nature of each of the dominant {001}, {110}, and {200} facets. The {200} facet was found to be significantly rougher than the other two; whereas, the {110} was characterized by a higher percentage of exposed DMF molecules compared to the other two facets. Specific scanning electron microscopy and contact angle measurements were used to experimentally detect differences among the three facets and validate the modelling results.

Tuning Rate‐Limiting Factors for Graphite Anodes in Fast‐Charging Li‐Ion Batteries

AbstractLocalized high‐concentration electrolyte (LHCE) is considered to be a promising substitution for the conventional carbonate electrolytes in fast‐charging Li‐ion batteries. However, the rate‐determining steps (RDS) for fast‐charging electrodes (i.e., graphite anode) in LHCE remain unclear. Herein, a typical localized high‐concentration electrolyte consisting of lithium bis(fluorosulfonyl)imide in dimethoxyethane with 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether as a diluent is selected to investigate the RDS of lithiation process in graphite anode, including the diffusion of solvated Li+ in the electrolyte, the desolvation behavior of solvated Li+, the Li+ transfer in solid electrolyte interphase (SEI) on the graphite surface, and the Li+ diffusion in bulk graphite. The results indicated that the rate performance of graphite anode in LHCE lies in the balance between Li+ desolvation process and Li+ migration in SEI. Through the regulation of solvated Li+ structure and SEI component, excellent fast‐charging performance can be obtained in the LHCE. The present studies not only offer fresh insights in the mechanistic understanding of fast‐charging batteries, but also provide new clues to the performance improvement of graphite anodes.

Plasma-assisted aerogel interface engineering enables uniform Zn2+ flux and fast desolvation kinetics toward zinc metal batteries

The poor reversibility of Zn anodes induced by dendrite growth, surface passivation, and corrosion, severely hinders the practical applicability of Zn metal batteries. To address these issues, a plasma-assisted aerogel (PAG) interface engineering was proposed as efficient ion transport modulator that can simultaneously regulate uniform Zn2+ flux and desolvation behavior during battery operation. The PAG with ordered mesopores acted as an ion sieve to homogenize Zn deposition and accelerate Zn2+ flux, which is favorable for corrosion resistance and dendrite suppression. Importantly, the plasma-assisted aerogel with abundant hydrophilic groups can facilitate the desolvation kinetics of Zn2+ due to the multiple hydrogen-bonding interaction with the activated water molecules, thus accelerating the Zn2+ migration kinetics. Consequently, the Zn/Zn cell assembled with PAG-modified separator demonstrates stable plating and stripping behavior (over 1400 h at 1 mA cm−2) and high Coulombic efficiency (99.8% at 1 mA cm−2 after 1100 cycles), and the Zn||MnO2 full cell shows excellent long-term cycling stability and maintains a high capacity of 154.9 mA h g−1 after 1000 cycles at 1 A g−1. This study provides a feasible approach for the large-scale fabrication of aerogel functionalized separators to realize ultra-stable Zn metal batteries.

Saccharin Sodium Coupling Fluorinated Solvent Enabled Stable Interface for High-Voltage Li-Metal Batteries.

Optimizing the electrode/electrolyte interface structure is the key to realizing high-voltage Li-metal batteries (LMBs). Herein, a functional electrolyte is introduced to synergetically regulate the interface layer structures on the high-voltage cathode and the Li-metal anode. Saccharin sodium (NaSH) as a multifunctional electrolyte additive is employed in fluorinated solvent-based electrolyte (FBE) for robust interphase layer construction. On the one hand, combining the results of ex-situ techniques and in-situ electrochemical dissipative quartz crystal microbalance (EQCM-D) technique, it can be seen that the solid electrolyte interface (SEI) layer constructed by NaSH-coupled fluoroethylene carbonate (FEC) on Li-metal anode significantly inhibits the growth of lithium dendrites and improves the cyclic stability of the anode. On the other hand, the experimental results also confirm that the cathode-electrolyte interface (CEI) layer induced by NaSH-coupled FEC effectively protects the active materials of LiCoO2 and improves their structural stability under high-voltage cycling, thus avoiding the material rupture. Moreover, theoretical calculation results show that the addition of NaSH alters the desolvation behavior of Li+ and enhances the transport kinetics of Li+ at the electrode/electrolyte interface. In this contribution, the LiCoO2ǁLi full cell containing FBE+NaSH results in a high capacity retention of 80% after 530 cycles with a coulombic efficiency of 99.8%.

Catalyzing Desolvation at Cathode-Electrolyte Interface Enabling High-Performance Magnesium-Ion Batteries.

Magnesium ion batteries (MIBs) are expected to be the promising candidates in the post-lithium-ion era with high safety, low cost and almost dendrite-free nature. However, the sluggish diffusion kinetics and strong solvation capability of the strongly polarized Mg2+ are seriously limiting the specific capacity and lifespan of MIBs. In this work, catalytic desolvation is introduced into MIBs for the first time by modifying vanadium pentoxide (V2O5) with molybdenum disulfide quantum dots (MQDs), and it is demonstrated via density function theory (DFT) calculations that MQDs can effectively lower the desolvation energy barrier of Mg2+, and therefore catalyze the dissociation of Mg2+-1,2-Dimethoxyethane (Mg2+-DME)bonds and release free electrolyte cations, finally contributing to a fast diffusion kinetics within the cathode. Meanwhile, the local interlayer expansion can also increase the layer spacing of V2O5 and speed up the magnesiation/demagnesiation kinetics. Benefiting from the structural configuration, MIBs exhibit superb reversible capacity (≈300mAhg-1 at 50mAg-1) and unparalleled cycling stability (15 000 cycles at 2Ag-1 with a capacity of ≈70mAhg-1). This approach based on catalytic reactions to regulate the desolvation behavior of the whole interface provides a new idea and reference for the development of high-performance MIBs.

Tunable Zn2+ de-solvation behavior in MnO2 cathodes via self-assembled phytic acid monolayers for stable aqueous Zn-ion batteries.

Sluggish ion diffusion kinetics at the electrode/electrolyte interface leads to insufficient rate capability and poor structural reversibility, which are mainly attributed to the hydrated Zn2+ migration process being inhibited due to its huge de-solvation energy barriers. Herein, a self-assembly method is proposed in which a multifunctional monolayer with phytic acid (PA) is coated on the surface of MnO2 strongly attaching to the substrate with the formation of chemical bonding to effectively prevent the dissolution of PA in the electrolyte. Due to the negative charge and inherent ultra-hydrophilicity of PA, modified MnO2 demonstrates stronger adsorption of positive ions and captures reactive water molecules, easily accelerating the de-solvation process of interfacial hydrated Zn2+, efficiently achieving reversible Zn2+ insertion/extraction. Meanwhile, the coating layers can protect the substrate from attack by active water molecules, thus inhibiting cathode dissolution during battery cycling. Experimental characterization studies reveal that the protected MnO2 cathode exhibits a remarkable specific capacity of 273 mA h g-1 with a zinc intercalation capacity contribution of more than 60% at a current density of 0.1 A g-1. Additionally, even at a high current density of 1 A g-1, it maintains a capacity of 197 mA h g-1, far exceeding that of pure MnO2. Furthermore, the Zn-ion pouch cell, serving as a proof of concept, achieves an impressive energy density of 300 W h kg-1 and exhibits remarkable capacity retention of 77% even after 100 cycles. This work offers a universal strategy for expediting the de-solvation process of hydrated Zn2+ on the surface of manganese-based cathodes in aqueous zinc-ion batteries.

Regulating the Interfacial Charge Density by Constructing a Novel Zn Anode-Electrolyte Interface for Highly Reversible Zn Anode.

Aqueous zinc-ion batteries (AZIBs) have attracted considerable attention. However, due to the uneven distribution of charge density at Zn anode-electrolyte interface, severe dendrites and corrosion are generated during cycling. In this work, a facile and scalable strategy to address the above-mentioned issues has been proposed through regulating the charge density at Zn anode-electrolyte interface. As a proof of concept, amidinothiourea (ATU) with abundant lone-pair electrons is employed as an interfacial charge modifier for Zn anode-electrolyte interface. The uniform and increased interfacial charge distribution on Zn anode-electrolyte interface has been obtained. Moreover, the unique Zn-bond constructed between N atoms and Zn2+ as well as the hydrogen bonds are formed among ATU and Ac- anion/active H2 O, which promote the migration and desolvation behavior of Zn2+ at anode-electrolyte interface. Accordingly, at a trace concentration of 0.01 mg mL-1 ATU, these features endow Zn anode with a long cycling life (more than 800 h), and a high average Columbic efficiency (99.52 %) for Zn||Cu batteries. When pairing with I2 cathode, the improved cycling ability (5000 cycles) with capacity retention of 77.9 % is achieved. The fundamental understanding on the regulation of charge density at anode-electrolyte interface can facilitate the development of AZIBs.

Achieving stable zinc metal anodes by regulating ion transfer and desolvation behavior

Aqueous Zn ion batteries (AZIBs) are considered to be highly promising rechargeable secondary batteries. However, the growth of zinc dendrites and irreversible side reactions hinder its further application. In this paper, an artificial interfacial protective layer of phenol–formaldehyde resin (PF) was constructed to achieve high-performance zinc anode. There is a strong interaction between hydroxyl groups in PF and Zn ions. This interaction modulates the solvation sheath of Zn ions and promotes the desolvation of [Zn(H2O)6]2+, which reduces the side reactions induced by reactive H2O. Furthermore, the pore structure of PF provides ion-confinement effect to regulate the Zn ions flux, thus reducing the growth of dendrites caused by inhomogeneous deposition. Thus, the PF coating has the dual effect of fast desolvation and ion confinement, which is beneficial to the uniform Zn ions deposition and achieves highly stable zinc anodes. Consequently, the Zn@PF||MnO2 full cell can be stably cycled for 1500 cycles at 1.5 A/g and the capacity retention remains 82.4 %. This method provides a convenient and practical approach to tackle the problems of zinc anodes, and establishes the foundation for their further application.

Insight into the Desolvation of Organic Electrolyte Cations with Propylene Carbonate as a Solvent in Flat Pores: A First-Principles Calculation

Supercapacitors have many applications in new energy and other high-tech fields. The desolvation effect on ions affects the capacity size of supercapacitors, and there are few relevant studies published in this field at present. In this experiment, bilayer graphene (BG) with a layer spacing of 4–10 Å was used as a model of flat pores and was calculated with first-principles calculations, which can effectively simulate the adsorption behaviour of porous carbon. The reaction energies of ions, propylene carbonate, and ionic complexes in bilayer graphene with different layer spacings were calculated, and the desolvation behaviour of lithium salt cations (Li+), tetraethyl quaternary ammonium salt cations (TEA+), triethyl methyl quaternary ammonium salt cations (TEMA+), and bipyrrolidinium quaternary ammonium salt cations (SBP+) was investigated. The calculation was based on density functional compact bound (DFTB+) software. The calculated results show that in the stacked system, the complete desolvation size of the TEA+ reaches 5.6 Å, the complete desolvation size of the TEMA+ reaches 4.9 Å, the complete desolvation size of the SBP+ reaches 4.8 Å, and the complete desolvation size of the Li+ reaches 5.4 Å, with the organic electrolyte cations showing a positive trend in the complete desolvation size as the ion radius increases. An in-depth analysis of the data shows that Li+, TEA+, TEMA+, and SBP+ ion radii play a dominant role in the size of desolvation. The results of this paper provide an effective aid for the selection of organic electrolytes to increase the capacity of supercapacitors.

Insight into the Desolvation of Quaternary Ammonium Cation with Acetonitrile as a Solvent in Hydroxyl-Flat Pores: A First-Principles Calculation.

Supercapacitors have a wide range of applications in high-technology fields. The desolvation of organic electrolyte cations affects the capacity size and conductivity of supercapacitors. However, few relevant studies have been published in this field. In this experiment, the adsorption behavior of porous carbon was simulated with first-principles calculations using a graphene bilayer with a layer spacing of 4-10 Å as a hydroxyl-flat pore model. The reaction energies of quaternary ammonium cations, acetonitrile, and quaternary ammonium cationic complexes were calculated in a graphene bilayer with different interlayer spacings, and the desolvation behavior of TEA+ and SBP+ ions was described. The critical size for the complete desolvation of [TEA(AN)]+ was 4.7 Å, and the partial desolvation size ranged from 4.7 to 4.8 Å. The critical size for the complete desolvation of [SBP(AN)]+ was 5.2 Å, and the partial desolvation size ranged from 5.2 to 5.5 Å. As the ionic radius of the quaternary ammonium cation decreased, the desolvation size showed a positive trend. A density of states (DOS) analysis of the desolvated quaternary ammonium cations embedded in the hydroxyl-flat pore structure showed that the conductivity of the hydroxyl-flat pore was enhanced after gaining electrons. The results of this paper provide some help in selecting organic electrolytes to improve the capacity and conductivity of supercapacitors.

Electrolyte strategy toward the low-temperature Li-metal secondary battery

Lithium metal battery (LMB) always faces a huge challenge at low temperature due to the sluggish reaction kinetics. An effective electrolyte could well tackle the issues as it much determines the Li+ de-solvation behavior and solid electrolyte interface (SEI) formation, and further greatly influenced the Li deposition. A practicable and cost-effective electrolyte was proposed in this work which sophisticatedly handled the balance between the ion-transfer character, Li solvation and SEI requirement. Highly fluent methyl acetate (MA) and SEI-beneficial fluoroethylene carbonate (FEC) together with Li salt constituted an anti-freezing electrolyte with sufficient ion-conductivity. More importantly, appropriate coordination between salt and solvent facilitated the de-solvation stage in Li+-reduction, additionally, the dual salt of lithium bis(fluorosulfonyl)imide (LiFSI) and lithium difluoro(oxalate)borate (LiODFB) combining with LiNO3 additive endowed the electrolyte with wide electrochemical window and Al compatibility. With them, repetitive Li striping/plating was achieved at −40 °C, and Li/LiNi0.5Co0.2Mn0.3O2 (NCM) full cell could be stably cycled for more than 150 times.

Construction of Bio-inspired Film with Engineered Hydrophobicity to Boost Interfacial Reaction Kinetics of Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries typically suffer from sluggish interfacial reaction kinetics and drastic cathode dissolution owing to the desolvation process of hydrated Zn2+ and continual adsorption/desorption behavior of water molecules, respectively. To address these obstacles, a bio-inspired approach, which exploits the moderate metabolic energy of cell systems and the amphiphilic nature of plasma membranes, is employed to construct a bio-inspired hydrophobic conductive poly(3,4-ethylenedioxythiophene) film decorating α-MnO2 cathode. Like plasma membranes, the bio-inspired film can "selectively" boost Zn2+ migration with a lower energy barrier and maintain the integrity of the entire cathode. Electrochemical reaction kinetics analysis and theoretical calculations reveal that the bio-inspired film can significantly improve the electrical conductivity of the electrode, endow the cathode-electrolyte interface with engineered hydrophobicity, and enhance the desolvation behavior of hydrated Zn2+ . This results in an enhanced ion diffusion rate and minimized cathode dissolution, thereby boosting the overall interfacial reaction kinetics and cathode stability. Owing to these intriguing merits, the composite cathode can demonstrate remarkable cycling stability and rate performance in comparison with the pristine MnO2 cathode. Based on the bio-inspired design philosophy, this work can provide a novel insight for future research on promoting the interfacial reaction kinetics and electrode stability for various battery systems.

Lithium difluoro(bisoxalato) phosphate-based multi-salt low concentration electrolytes for wide-temperature lithium metal batteries: Experiments and theoretical calculations

Current knowledge and works on high-energy-density Li metal batteries (LMBs) mainly focus on their room-temperature performances. However, the wide-temperature properties of LMBs manifesting greater significance in their large-scale applications are rarely explored. In this work, two LiDFBOP-based multi-salt low-concentration electrolytes (LCEs) are proposed and further explored by experiments and theoretical calculations for wide-temperature LMBs. Molecular dynamics (MD) simulations reveal the weaker attractive interactions between solvent molecules in LCEs, thus resulting in the lower viscosity and freezing point. Specially, the Li+ in representative solvation structures of LCEs possesses accelerated desolvation behavior with low charge-transfer impedance in Li||Li symmetric cells. Furthermore, the thermally stable Li salts in LCEs manifest obvious effect in stabilizing Li metal anode, which contributes to forming a compact solid electrolyte interphase (SEI) layer with good mechanical properties and high ionic conductivity. Ultimately, the Li||LiNi0.7Co0.1Mn0.2O2 battery exhibits extraordinary electrochemical performances over a wide temperature range (−25 °C to 70 °C). This work provides a facile and practical design strategy for the wide-temperature LMBs.

Effect of pore structures on desolvation of carbon materials as the electrode materials of supercapacitors: A first-principles study

More and more attention has been paid to the role of the desolvation effect of ions in the electrolyte for supercapacitor in improving its capacitance. We have previously calculated that the complete desolvation size of Li+, Na+, and K+ in the basal plane pore (BPP) is 4.7 Å, 4.4 Å, and 4.4 Å, but the desolvation of the edge plane pore (EPP) is not considered. So in this work, the complete desolvation behaviour of Li+, Na+, and K+ at the EPP in the pore structure of porous carbon materials in the aqueous solution is studied by first-principles calculations. The calculation results show that the solvated Li+ can be completely desolvated when the pore size of EPP is less than 3.61 Å, while the solvated Na+ and K+ will not be desolvated under any pore size of EPP. Combining the work of this paper with our previous work, solvated Li+ has desolvation behaviour in both EPP and basal plane pore (BPP). Four models of pores are constructed by the combination of EPP and BPP to discuss the storage of desolvated Li+ in porous carbon materials. The calculation results show that the necking flask like EPP-BPP pore with ∼ 3.61 Å outer pore and ∼ 7.4 Å inner pore can accommodate more Li+ improving the capacitance of the supercapacitors. The desolvation mechanism of EPP and BPP on the solvated ions has important theoretical guiding significance for designing the pore structure of porous carbon materials.

Ten Thousand-Cycle Ultrafast Energy Storage of Wadsley-Roth Phase Fe-Nb Oxides with a Desolvation Promoting Interfacial Layer.

Developing advanced electrode materials with enhanced charge-transfer kinetics is the key to realizing fast energy storage technologies. Commonly used modification strategies, such as nanoengineering and carbon coating, are mainly focused on electron transfer and bulk Li+ diffusion. Nonetheless, the desolvation behavior, which is considered as the rate-limiting process for charge-storage, is rarely studied. Herein, we designed a nitridation layer on the surface of Wadsley-Roth phase FeNb11O29 (FNO-x@N) to act as a desolvation promoter. Theoretical calculations demonstrate that the adsorption and desolvation of solvated Li+ is efficiently improved at FNO-x@N/electrolyte interphase, leading to the reduced desolvation energy barrier. Moreover, the nitridation layer can also help to prevent solvent cointercalation during Li+ insertion, leading to advantageous shrinkage of block area and reduced volume change of lattice cell during cycling. Consequently, FNO-x@N exhibits a high-rate capacity of 129.7 mAh g-1 with negligible capacity decay for 10 000 cycles.