Long-life Batteries Research Articles

Modulating solvated structure of Zn2+ and inducing surface crystallography by a simple organic molecule with abundant polar functional groups to synergistically stabilize zinc metal anodes for long-life aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have attracted significant attention owing to their inherent security, low cost, abundant zinc (Zn) resources and high energy density. Nevertheless, the growth of zinc dendrites and side reactions on the surface of Zn anodes during repeatedly plating/stripping shorten the cycle life of AZIBs. Herein, a simple organic molecule with abundant polar functional groups, 2,2,2-trifluoroether formate (TF), has been proposed as a high-efficient additive in the ZnSO4 electrolyte to suppress the growth of Zn dendrites and side reaction during cycling. It is found that TF molecules can infiltrate the solvated sheath layer of the hydrated Zn2+ to reduce the number of highly chemically active H2O molecules owing to their strong binding energy with Zn2+. Simultaneously, TF molecules can preferentially adsorb onto the Zn surface, guiding the uniform deposition of Zn2+ along the crystalline surface of Zn(002). This dual action significantly inhibits the formation of Zn dendrites and side reactions, thus greatly extending the cycling life of the batteries. Accordingly, the Zn//Cu asymmetric cell with 2 % TF exhibits stable cycling for more than 3,800 cycles, achieving an excellent average Columbic efficiency (CE) of 99.81 % at 2 mA cm−2/1 mAh cm−2. Meanwhile, the Zn||Zn symmetric cell with 2 % TF demonstrates a superlong cycle life exceeding 3,800 h and 2,400 h at 2 mA cm−2/1 mAh cm−2 and 5 mA cm−2/2.5 mAh cm−2, respectively. Simultaneously, the Zn//VO2 full cell with 2 % TF possesses high initial capacity (276.8 mAh/g) and capacity retention (72.5 %) at 5 A/g after 500 cycles. This investigation provides new insights into stabilizing Zn metal anodes for AZIBs through the co-regulation of Zn2+ solvated structure and surface crystallography.

Activating the Intrinsic Zincophilicity of PAM Hydrogel to Stabilize the Metal-Electrolyte Dynamic Interface for Stable and Long-Life Zinc Metal Batteries.

As a potential material to solve rampant dendrites and hydrogen evolution reaction (HER) problem of aqueous zinc metal batteries (AZMB), hydrogel electrolytes usually require additional additives or multi-molecular network strategies to solve existing problems of ionic conductivity, mechanical properties and interface stability. However, the intrinsic zincophilic properties of the gel itself are widely neglected leading to the addition of additional molecules and the complexity of the preparation process. In this work, we innovatively utilize the characteristics of acrylamide's high zincophilic group density, activating the intrinsic zincophilic properties of PAM gel through a simple concentration control strategy which reconstructs a novel zinc-electrolyte interface different from conventional PAM electrolyte. The activated novel gel electrolyte with intrinsic zincophilic properties has high ionic conductivity and effectively suppresses water activity, thereby inhibiting HER corrosion. Meanwhile, it induces uniform deposition of (002) crystal planes, leading to excellent deposition kinetics and long cycle life, thereby ensuring high interfacial stability. Compared with conventional PAM gel electrolytes, the activated zincophilic group-rich hydrogel maintained excellent cycling stability (1 mA/cm2, 1 mAh/cm2) over 2250 hours; The Zn//MnO₂ coin cell using novel zincophilic group -rich hydrogel still retains a high specific capacity of more than 170 mAh/g at 0.5 A/g after 1000 cycles.

Synergism of preintercalated manganese ions and lattice water in vanadium oxide cathodes for high-capacity and long-life Zn-ion batteries

Aqueous Zn-ion batteries (AZIBs) are recognized as a promising energy storage system with intrinsic safety and low cost, but its applications still rely on the design of high-capacity and stable-cycling cathode materials. In this work, we present an intercalation mechanism-based cathode materials for AZIB, i.e. the vanadium oxide with pre-intercalated manganese ions and lattice water (noted as MVOH). The synergistic effect between Mn2+ and lattice H2O not only expands the interlayer spacing, but also significantly enhances the structural stability. Systematic in-situ and ex-situ characterizations clarify the Zn2+/H+ co–(de)intercalation mechanism of MVOH in aqueous electrolyte. The demonstrated remarkable structure stability, excellent kinetic behaviors and ion-storage mechanism together enable the MVOH to demonstrate satisfactory specific capacity of 450 mA h g−1 at 0.2 A g−1, excellent rate performance of 288.8 mA h g−1 at 10 A g−1 and long cycle life over 20,000 cycles at 5 A g−1. This work provides a practical cathode material, and contributes to the understanding of the ion-intercalation mechanism and structural evolution of the vanadium-based cathode for AZIBs.

Flexible bidirectional pulse charging regulation achieving long-life lithium-ion batteries

Typical application scenarios, such as vehicle to grid (V2G) and frequency regulation, have imposed significant long-life demands on lithium-ion batteries. Herein, we propose an advanced battery life-extension method employing bidirectional pulse charging (BPC) strategy. Unlike traditional constant current charging methods, BPC strategy not only achieves comparable charging speeds but also facilitates V2G frequency regulation simultaneously. It significantly enhances battery cycle ampere-hour throughput and demonstrates remarkable life extension capabilities. For this interesting conclusion, adopting model identification and postmortem characterization to reveal the life regulation mechanism of BPC: it mitigates battery capacity loss attributed to loss of lithium-ion inventory (LLI) in graphite anodes by intermittently regulating the overall battery voltage and anode potential using a negative charging current. Then, from the perspective of internal side reaction, the life extension mechanism is further revealed as inhibition of solid electrolyte interphase (SEI) and lithium dendrite growth by regulating voltage with a bidirectional pulse current, and a semi-empirical life degradation model combining SEI and lithium dendrite growth is developed for BPC scenarios health management, the model parameters are identified by genetic algorithm with the life simulation exhibiting an accuracy exceeding 99%. This finding indicates that under typical rate conditions, adaptable BPC strategies can extend the service life of LFP battery by approximately 123%. Consequently, the developed advanced BPC strategy offers innovative perspectives and insights for the development of long-life battery applications in the future.

High-voltage and long-life aqueous lithium-ion batteries based on polyanionic framework structured Na3V2(PO4)3 and NbOPO4 in novel deep eutectic solvents

High-voltage and long-life aqueous lithium-ion batteries based on polyanionic framework structured Na3V2(PO4)3 and NbOPO4 in novel deep eutectic solvents

The effects of fluorine doping on the structure, interface and electrochemical properties of lithium titanate

Enhancing the electronic and ionic conductivity of Li4Ti5O12 electrode materials, as well as suppressing the interface reaction between Ti4+ on the surface of Li4Ti5O12 and the electrolyte, is one of the key factors in preparing high-power and long-life Li4Ti5O12 lithium-ion batteries. To tackle these challenges, fluorine ions with strong electronegativity was chosen as dopants to engineer fluorine-doped Li4Ti5O12 electrode materials. Fluorine ion doping changes the surface state of Li4Ti5O12, increases the interface compatibility, suppresses the reactivity between Li4Ti5O12 and the electrolyte, and forms a uniform SEI film during cycling. Moreover, fluorine ion doping induces the generation of oxygen vacancies and improves the crystallinity of Li4Ti5O12, thereby fostering improved electronic and ionic transport kinetics. The above appealing features enables the prepared fluorine-doped Li4Ti5O12 material demonstrates exceptional high-rate performance, delivering specific capacities of 175 mAh·g−1/0.5C, 159 mAh·g−1/10C, and 138 mAh·g−1/50C. In essence, the fluoride ion doping strategy holds profound implications for enhancing electrode interface characteristics, transport kinetics, and the fabrication of high-power lithium-ion batteries.

Architecting obliquitous and rich ion transport bridges in polymer electrolytes for room temperature long-life solid-state batteries

Solid-state lithium-metal batteries are a viable energy storage device due to their high energy density and safety features. Solid-state electrolytes are integral to maintain safety by restricting the uncontrolled growth of lithium dendrites and hindering the side reactions. However, their practical application is hampered by low ionic conductivity, undesirable interfacial contacts, severe polarization, and unbefitting operation temperature. Herein, a composite quasi-solid-state polymer electrolyte is designed via in-situ polymerization of suspension electrolyte with fumed aluminum trioxide nanoparticles and the addition of poly (ethylene glycol) diacrylate, resulting in enrichment short polymer bridges for Li ion transferring (ionic conductivity reach to 4.1 × 10−4 S cm−1 at room temperature). Remarkably, the polymer electrolyte with tortuous structural properties can afford a higher lateral Li ion diffusion, which facilitates the suppression of dendrite. Additionally, the addition of aluminum trioxide can improve the electrochemical stability, indicating a strong correlation between the electrolyte's physicochemical properties and the solvation structure of the precursor. As expected, this type of electrolyte-based Li metal batteries coupled with LiNi0.8Co0.1Mn0.1O2 and LiNi0.6Co0.2Mn0.2O2 cathodes can enable stable operation for both coin and pouch cells, paving the way for exploring a series of architectures such as flexible and custom shaped batteries.

Interface-Targeting Carrier-Catalytic Integrated Design Contributing to Lithium Dihalide-Rich SEI toward High Interface Stability for Long-Life Solid-State Lithium-Metal Batteries.

The generation of solid electrolyte interphase (SEI) largely determines the comprehensive performance of all-solid-state batteries. Herein, a novel "carrier-catalytic" integrated design is strategically exploited to in situ construct a stable LiF-LiBr rich SEI by improving the electron transfer kinetics to accelerate the bond-breaking dynamics. Specifically, the high electron transport capacity of Br-TPOM skeleton increases the polarity of C-Br, thus promoting the generation of LiBr. Then, the enhancement of electron transfer kinetics further promotes the fracture of C-F from TFSI- to form LiF. Finally, the stable and homogeneous artificial-SEI with enriched lithium dihalide is constructed through the in situ co-growth mechanism of LiF and LiBr, which facilitatse the Li-ion transport kinetics and regulates the lithium deposition behavior. Impressively, the PEO-Br-TPOM paired with LiFePO4 delivers ultra-long cycling stability over 1000 cycles with 81 % capacity retention at 1 C while the pouch cells possess 88 % superior capacity retention after 550 cycles with initial discharge capacity of 145 mAh g-1at 0.2 C in the absence of external pressure. Even under stringent conditions, the practical pouch cells possess the practical capacity with stable electric quantities plateau in 30 cycles demonstrates its application potential in energy storage field.

Stabilizing high-Ni cathodes with gradient surface Ti-enrichment

High-Ni cathodes are being intensely pursued worldwide for electric vehicles and other energy-dense applications due to their high capacity and low cost. However, structural instabilities during electrochemical cycling and when subjected to thermal treatment have been the major issues hindering their practical deployment. We here report a rational design of coating-integrated-into-synthesis protocol for fabricating surface Ti-enriched LiNi0.8Mn0.1Co0.1O2 (NMC811#Ti) material. The coating to intermediates is crucial to obtain high structural ordering, both in the bulk and surface of high-Ni cathodes, and the Ti substitute has a unique tri-valence (Ti3+) in a gradient surface distribution. The simulations of projected density of states in the atomistic understanding further certify significantly enhanced stability of lattice oxygen for the NMC811 through such a Ti3+-based structure reinforcement. Consequently, the NMC811#Ti cathode delivers a high capacity up to 200 mAh g−1 at 0.1 C, along with superior stabilities during air-storage and thermal treatment (up to 297 °C at the fully charged state under differential scanning calorimetric measurements). The corresponding NMC811#Ti||graphite full cell exhibits a desired 83.6 % capacity retention after 1000 cycles at 0.5 C in a voltage range of 2.8–4.3 V. This work demonstrates a delicate surface reinforcement to stabilize high-Ni cathodes for long-life and safe lithium-ion batteries.

Constructing highly safe and long-life calcium ion batteries based on hydratedvanadium oxide cathodes featuring a pillar structure

Constructing highly safe and long-life calcium ion batteries based on hydratedvanadium oxide cathodes featuring a pillar structure

Reduced graphene oxide assembled on the Si nanowire anode enabling low passivation and hydrogen evolution for long-life aqueous Si-air batteries

Silicon-air batteries (SABs), a new type of semiconductor air battery, have a high energy density. However, some side reactions in SABs cause Si anodes to be covered by a passivation layer to prevent continuous discharge, and the anode utilization rate is low. In this work, reduced graphene oxide (RGO) fabricated via high-temperature annealing or L-ascorbic acid (L.AA) reduction was first used to obtain Si nanowires/RGO-1000 (Si NWs/RGO-1000) and Si nanowires/RGO-L.AA (Si NWs/RGO-L.AA) composite anodes for SABs. It was found that RGO suppressed the passivation and self-corrosion reactions and that SABs using Si NWs/RGO-L.AA as the anode can discharge for more than 700 hours, breaking the previous performance of SABs, and that the specific capacity was increased by 90.8% compared to bare Si. This work provides a new solution for the design of high specific capacity SABs with nanostructures and anode protective layers.

2D ZIF-8 derived N-doped porous carbon nanosheets for high-performance Li-Se batteries

Lithium-selenium (Li-Se) batteries have attracted increasing attention because of excellent carbonate electrolyte compatibility, comparable theoretical volumetric specific capacity and high electrical conductivity. However, there are still unavoidable issues such as large volume expansion, rapid capacity decay and slow electrochemical reaction kinetics for practical applications. In this work, we report 2D ZIF-8 derived N-doped porous carbon nanosheets (NPC-NS) as Se host for high-performance Li-Se batteries. The unique 2D structure of Se@NPC-NS facilitates Li+ diffusion and charge transfer, thus the Se@NPC-NS cathode exhibits fast electrochemical reaction kinetics. In addition, the N doping enhances electronic conductivity and porous structure mitigates the volume expansion. As a result, the Se@NPC-NS cathode delivers a high reversible capacity of 585 mAh/g with a capacity retention of 99.1 % at 0.5C (1C = 675 mA g−1) after 225 cycles. Especially after 500 cycles at a high current density of 10C, the Se@NPC-NS cathode still displays a reversible specific capacity of 307 mAh/g with only 0.03 % capacity decay per cycle. This work would shed some light on the 2D carbon host as Se-based cathode for high-rate and long-life performance Li-Se batteries.

Intralayer ordered structure engineering for long-life Mn-based potassium-ion battery cathodes

Mn-based layered oxides have become one of the most promising cathode materials in potassium-ion batteries (PIBs) due to their high theoretical specific capacity. Nonetheless, the Jahn-Teller effect of Mn3+ leads to lattice distortion and a high K+ migration barrier, resulting in structural instability during the charge/discharge processes. To effectively overcome these problems, this work provides a method to change electronic energy levels to suppress the Jahn-Teller effect through the synergistic regulation of multiple specific element doping. The X-ray diffraction pattern of K0.4Mn0.7Ti0.1Ni0.1Cu0.1O2 shows its P3-type structure. The electrochemical test results demonstrate that K0.4Mn0.7Ti0.1Ni0.1Cu0.1O2 exhibits superior rate capacity, higher discharge specific capacity, and significant cycling stability (with a capacity retention rate of 80 % after 860 charge/discharge cycles). The in-situ X-ray diffraction pattern demonstrates the high reversibility of the electrochemical process of K+ insertion/extraction. First-principles calculations have confirmed that the electronic energy levels of K0.4Mn0.7Ti0.1Ni0.1Cu0.1O2 have better dispersion, the K+ migration channel has been effectively optimized, and the K+ migration barrier has been reduced. This study provides a significant and effective reference for the design of advanced PIBs with high performance.

Hierarchical porous nanofibers comprising N-doped graphitic C and ZIF-8 derived hollow N-doped C nanocages for long-life K-ion battery anodes

Hierarchical porous carbon nanofibers (NFs) are designed via electrospinning, followed by simple carbonization, and applied as the anode for K-ion batteries (KIBs). The carbonization process is optimized to simultaneously satisfy sufficient graphitization of polyacrylonitrile (PAN)-derived soft carbon and complete conversion of zeolitic imidazolate framework-8 (ZIF-8) to hollow N-doped C nanocages. The prepared NFs through an optimized carbonization consists of porous and hollow N-doped C nanocages, which are encapsulated within the conductive graphitic carbon (GC) matrix, that acts as an efficient electron transport pathway. Moreover, the interconnected porous and hollow nanocages ensure a high contact area between the electrode and electrolyte and reduces the K-ion diffusion length. The N-doped GC with high electrical conductivity in the structure demonstrates reinforcing structural integrity as well as providing additional transport pathways for the unique electron transport. Therefore, the hierarchical porous carbon NFs show outstanding energy storage properties, such as stable cycle performance up to 10,000 cycles at the high current density of 1.0 A g-1 with high areal loading mass (1.8–1.9 mg cm−2) of the active material, which clearly suggests the structural advantages of the nanostructure introduced in this study.

P/s-orbital hybridization induced by Mg-doping to active Na sites in Na2FePO4F cathode for long-life and high-rate sodium-ion batteries

The iron-based fluorophosphate Na2FePO4F (NFPF) is considered as a potential cathode for sodium-ion batteries due to the low-cost, non-toxicity and appropriate working voltage. However, the inferior intrinsic electronic conductivity and the restrained active Na sites bring the limits for full realization of electrochemical properties. Herein, Mg2+ with d0 orbital was introduced in FeO4F2 structure, aimed at activating the Na+ at Na1 site and enhancing the electronic conductivity. Different from the 3d transition metal (TM) elements that form 3d-O2p orbital interactions in the FeO4F2 structure, the Mg with d° contributes p and s orbitals mainly in Mg-O bonds, which corresponds to more stable orbital interaction and lattice structure. The electron distribution of bridge O due to the Mg-doping leads to the wooden barrel effect near the Mg site, thus activating Na+ at Na1 site by lowering the energy barrier of Na+ migration from Na1 to Na2 site. Hence, the obtained NFMPF electrode delivers high specific capacity (121.4 vs. 108.7 mAh g−1 at 0.1 C) and better cycling stability (73.8% vs. 54.2 % after 1000 cycles at 20 C). Overall, regulating the electronic structure and activating Na+ at inactive site is the key to break the bottleneck of low activity, which can be an effective strategy to design cathode materials with excellent electrochemical performance.

Synergistically accelerating capture and catalytic conversion of polysulfides by Co@NCNT-MoSe2 nanocomposite modified separator for advanced Lithium-Sulfur batteries

Lithium-sulfur (Li-S) battery with a high theoretical energy density (2600 Wh·kg−1) is considered as a promising energy storage system. However, the shuttle effect and the sluggish redox kinetics of lithium polysulfides (LiPSs) lead to low sulfur utilization. A multifunctional layer modified on separator, as a collaborator of capturer-catalyst-conductor, is be regarded as an effective strategy to solve these problems. Herein, the Co@NCNT-MoSe2 nanocomposite as a modified layer is synthesized with a mesoporous structure by the hydrothermal reaction, in which a large number of transparent MoSe2 nanosheets grow outside NCNT embedded with Co nanoparticles, forming a flower-like outer walls of tube. The modified layer displays the significant features of capturing and catalytic conversion toward LiPSs, attributing to strong adsorption abilities, abundant catalytic active sites, and efficient transferring pathway of electron/Li+. Benefitting from these alluring properties, the results demonstrate that the modified separator offers a high discharge capacity of 983.2 mAh·g−1 at 0.2C after 200 cycles. Even at 2C, after long-term 1000 cycles, it still shows a superb capacity of 725 mAh·g−1 accompanied by a low capacity fading of 0.042 % per cycle. More notably, at 0.2C, the modified separator can realize an ideal areal capacity of 5.24 mAh·cm−2 under high S load (5 mg·cm−2) and poor electrolyte (7.5 μL·mg−1). Therefore, this work will provide a new insight on the development of multifunctional separators to achieve a long-life battery with high sulfur utilization by restraining shuttle effect and accelerate redox kinetics of LiPSs.

A Hydrogel Electrolyte with High Adaptability over a Wide Temperature Range and Mechanical Stress for Long-Life Flexible Zinc-Ion Batteries.

Flexible zinc-ion batteries have garnered significant attention in the realm of wearable technology. However, the instability of hydrogel electrolytes in a wide-temperature range and uncontrollable side reactions of the Zn electrode have become the main problems for practical applications. Herein, N,N-dimethylformamide (DMF) to design a binary solvent (H2O-DMF) is introduced and combined it with polyacrylamide (PAM) and ZnSO4 to synthesize a hydrogel electrolyte (denoted as PZD). The synergistic effect of DMF and PAM not only guides Zn2+ deposition on Zn(002) crystal plane and isolates H2O from the Zn anode, but also breaks the hydrogen bonding network between water to improve the wide-temperature range stability of hydrogel electrolytes. Consequently, the symmetric cell utilizing PZD can stably cycle over 5600 h at 0.5mA cm- 2@0.5 mAh cm-2. Furthermore, the Zn//PZD//MnO2 full cell exhibits favorable wide-temperature range adaptability (for 16000 cycles at 3 A g-1 under 25 °C, 750 cycles with 98 mAh g-1 at 0.1 A g-1 under -20 °C) and outstanding mechanical properties (for lighting up the LEDs under conditions of pressure, bending, cutting, and puncture). This work proposes a useful modification for designing a high-performance hydrogel electrolyte, which provides a reference for investigating the practical flexible aqueous batteries.

Study on the electrochemical reaction mechanism of non-corrosive and long-life rechargeable aluminum battery

Study on the electrochemical reaction mechanism of non-corrosive and long-life rechargeable aluminum battery

Synergistic interaction between amphiphilic ion additive groups for stable long-life zinc ion batteries

The uneven deposition of zinc and hydrogen generation at the zinc anode interface constitute major impediments to the lifespan of aqueous zinc-ion batteries. Herein, an amphoteric ion additive, choline phosphate (CP), is proposed to stabilize the battery anode interface. The remarkable interplay between choline ions and phosphate groups assumes a pivotal role in homogenizing zinc ion deposition and regulating the behavior of free water molecules. Due to the negative electric field adsorption on the surface of the zinc anode, the positively charged choline ions will be adsorbed on its surface preferentially and prevent the approach of water molecules. The phosphate group interacts strongly with the zinc ion, permeating the solvated structure of these ions, regulating zinc ion flux, and immobilizing free water molecules through hydrogen bonding to impede unwanted side reactions. In summary, using CP additives yields a profound enhancement in enabling significantly extended cycle lifespans of both Zn//Zn symmetric batteries and LiFePO4 full batteries.

Concentrated weak hydrated electrolytes towards ultra-stable high-voltage zinc ion batteries

Hydrogen evolution reactions (HER), dendritic growth, narrow electrochemical windows, and dissolution of cathode materials severely limit the development of aqueous zinc metal batteries. Herein, the unique bisphenylsulfonamide anion (BBI−) is employed to reduce the ion-dipole interaction between Zn2+ and H2O by complexing Zn2+ to suppress H2O decomposition. Meanwhile, the solvent sheath structure of Zn2+-BBI− coordination can provide a large nucleation overpotential, thus producing uniform deposition to suppress dendrites. The hydrogen bonds between BBI− and H2O effectively limit the diffusion of H2O, thereby reducing the dissolution of the water-soluble cathode material into the electrolyte. Both experimental and simulated results are carried out and quantitively confirm the ion paring, hydrogen bond and solvent effect evolution of Zn(BBI)2 electrolytes. This concentrated electrolyte enables Zn||Zn symmetric cells to achieve a superlong cycling life of over 7100 h even at a current of 2 mA cm−2 and capacity of 2 mAh cm−2, while the high mass loading Zn||NaV3O8·1·5H2O and Zn||Zn3(Fe(CN)6)2 cells also exhibit excellent cycling performance at a cut-off voltage of 2.1 V. The findings of this work point to a very promising strategy for the development of long-life aqueous batteries.