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The value of considerable residual energy in waste Li-ion batteries (WLIBs) is always neglected. At present, "this energy" is always wasted during the discharge process of WLIBs. However, if this energy could be reused, it would not only save a lot of energy but also avoid the discharge step of recycling of WLIBs. Unfortunately, the instability of WLIBs potential is a challenge to efficient utilization of this residual energy. Here, we propose a method that could regulate the cathode potential and current of the battery by simply adjusting the solution pH to utilize 35.08%, 88.4%, and 84.7% of the residual energy for removing heavy metal ions from wastewater, removing Cr (VI) from wastewater, and recovering copper from the solution, respectively. By taking advantage of the high internal resistance R of WLIBs and the sudden change of battery current I caused by iron passivation on the positive electrode of the battery, this method could induce the response of overvoltage η (η = IR) inside the battery at different pH levels to regulate the cathode potential µ of the battery to the three intervals. The potential ranges of the battery cathode corresponding to pH < 3.4, pH ≈ 3.4, and pH > 4 were µ > -0.47V, -0.47V < µ < -0.82V, and µ < -0.82V, respectively. This study provides a promising way and theoretical basis for the development of technologies for reusing residual energy in WLIBs.
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In this study, we clarify the liquid structure formed at the interface between LiCoO2 (LCO), the cathode material of Li-ion batteries, and propylene carbonate (PC), which is used as a solvent in the electrolyte, on a molecular scale. We apply sparse modeling-based modal analysis to force spectroscopy data measured by frequency modulation atomic force microscopy (FM-AFM) and show that each component in the FM-AFM force curve, such as oscillatory solvation force, background, and noise, can be automatically decomposed. Moreover, by combining detailed force curve analysis with solid/liquid interface simulations based on first-principles calculation, we have identified that there are distinct damped vibrational modes in the force curves at the LCO/PC interface with a period of about 0.57 nm and those with shorter periods, which likely correspond to the solvation forces associated with bulk-state PC molecules and those with PC molecules in "lying down" orientations.
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Ultrafast high-capacity lithium-ion batteries are extremely desirable for portable electronic devices, where Si is the most promising alternative to the conventional graphite anode due to its very high theoretical capacity. However, the low electronic conductivity and poor Li-diffusivity limit its rate capability. Moreover, high volume expansion/contraction upon Li-intake/uptake causes severe pulverization of the electrode, leading to drastic capacity fading. Here, interface and morphology-engineered amorphous Si matrix is being reported utilizing a few-layer vertical graphene (VG) buffer layer to retain high capacity at both slow and fast (dis)charging rates. The flexible mechanical support of VG due to the van-der-Waals interaction between the graphene layers, the weak adhesion between Si and graphene, and the highly porous geometry mitigated stress, while the three-dimensional mass loading enhanced specific capacity. Additionally, the high electronic conductivity of VG boosted rate-capability, resulting in a reversible gravimetric capacity of ≈1270 mAh g-1 (areal capacity of ≈37 µAh cm-2) even after 100 cycles at an ultrafast cycling rate of 20C, which provides a fascinating way for conductivity and stress management to obtain high-performance storage devices.
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The unique anionic redox mechanism provides, high-capacity, irreversible oxygen release and voltage/capacity degradation to Li-rich cathode materials (LRO, Li1.2Mn0.54Co0.13Ni0.13O2). In this study, an integrated stabilized carbon-rock salt/spinel composite heterostructured layers (C@spinel/MO) is constructed by in situ self-reconstruction, and the generation mechanism of the in situ reconstructed surface is elucidated. The formation of atomic-level connections between the surface-protected phase and bulk-layered phase contributes to electrochemical performance. The best-performing sample shows a high increase (63%) of capacity retention compared to that of the pristine sample after 100 cycles at 1C, with an 86.7% reduction in surface oxygen release shown by differential electrochemical mass spectrometry. Soft X-ray results show that Co3+ and Mn4+ are mainly reduce in the carbothermal reduction reaction and participate in the formation of the spinel/MO rock-salt phase. The results of oxygen release characterized by Differential electrochemical mass spectrometry (DEMS) strongly prove the effectiveness of surface reconstruction.
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Covalent organic frameworks (COFs), featuring structural diversity, permanent porosity, and functional versatility, have emerged as promising electrode materials for rechargeable batteries. To date, amorphous polymer, COF, or their composites are mostly explored in lithium-ion batteries (LIBs), while their research in other alkali metal ion batteries is still in infancy. This can be due to the challenges that arise from large volume changes, slow diffusion kinetics, and inefficient active site utilization by the large Na+ or K+ ion. Herein, microwave-assisted imide-based 2D COF, TAPB-NDA covalently connected with amine-functionalized carbon nanotubes (TAPB-NDA@CNT) targeting the application in both Li-/Na-ion batteries, is synthesized. As-synthesized, TAPB-NDA@CNT50 displays the good performance as LIB cathode with a specific capacity of ≈138 mAh g-1 at 25 mA g-1, long cycling stability (81.2% retention after 2000 cycles at 300 mA g-1), with excellent reversible capacity retention of ≈79.6%. Similarly, TAPB-NDA@CNT50, when employed in sodium-ion battery (SIB), exhibited 136.7 mAh g-1 specific capacity at 25 mA g-1, retained ≈80% of the reversible capacity after 1000 cycles at 300 mA g-1 and showing excellent rate performance. The structural advantage of TAPB-NDA@CNT will encourage researchers to design COF-based cathodes for the alkali ion batteries.
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Anode materials storing large-scale lithium ions gradually decrease electrochemical performance due to severe volume changes during cycling. Therefore, there is an urgent need to develop anode materials with high electrochemical capacity and durability, without deterioration arising due to the volume changes during the electrochemical processes. To date, mesoporous materials have received attention as anode materials due to their ability to mitigate volume expansion, offer a short pathway for Li+ transport, and exhibit anomalous high capacity. However, the nano-frameworks of transition metal oxide collapse during conversion reactions, demanding an improvement in nano-framework structure stability. In this study, ordered mesoporous nickel manganese oxide (m-NMO) is designed as an anode material with a highly durable nanostructure. Interestingly, m-NMO showed better cycle performance and higher electrochemical capacity than those of nickel oxide and manganese oxide. Operando small-angle X-ray scattering and ex situ transmission electron microscopic results confirmed that the binary m-NMO sustained a highly durable nanostructure upon cycling, unlike the single metal oxide electrodes where the mesostructures collapsed. Ex situ X-ray absorption spectroscopy proved that nickel and manganese showed different electrochemical reaction voltages, and thus undergoes sequential conversion reactions. As a result, both elements can act as complementary nano-propping buffers to maintain stable mesostructure.
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High voltage cobalt-free spinel LiNi0.5Mn1.5O4 (LNMO) is well organized as a high-power cathode material for lithium (Li)-ion batteries, however, the weak interaction between the 3d orbital of the transition metal (TM) ions and the 2p orbital of oxygen (O) leads to the instability of crystal structural, hindering the long-term stable cycling of LNMO cathode especially at high temperatures. Here, a design strategy of orbital interaction is initiated to strengthen TM 3d-O 2p framework in P-doped LNMO (P-LNMO) by choosing phytic acid as P dopant, which can realize more uniform doping compared to regular phosphate. The results show that the enhancement of TM 3d-O 2p orbital interaction in P-LNMO can suppress the Jahn-Teller effect and subsequent dissolution of Mn, as well as lowers the energy barrier for Li ion insertion/extraction kinetics. As a result, superior electrochemical performances including high discharge capacity, stable cycling behavior and enhanced rate capability of P-LNMO are obtained. Significantly, the P-LNMO pouch cell shows great cycling stability with 97.4% capacity retention after 100 cycles.
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MXenes are known for their exceptional electrical conductivity and surface functionality, gaining interest as promising anode materials for Li-ion batteries. However, conventional 2D multilayered MXenes often exhibit limited electrochemical applicability due to slow ion transport kinetics and low structural stability. Addressing these challenges, this study develops a 3D flower-type double transition metal MXene, Mo2Ti2C3Clx, with precisely engineered in-plane mesoporosity using HF-free Lewis acid-assisted molten salt method, coupled with intercalation and freeze-drying. The molar ratio of Lewis acid to eutectic salts is meticulously controlled to create the mesoporosity, which is preserved through freeze-drying. Molecular dynamics (MD) simulations assess the impact of in-plane pore size on the structure and transport dynamics of electrolyte components. Density functional theory (DFT) shows that chlorine surface functional groups significantly reduce Li-ion diffusion barriers, thereby enhancing ion transport and battery performance. Electrochemical evaluations reveal that small-sized (2-5 nm) mesoporous Mo2Ti2C3Clx achieves a specific capacity of 324 mAh g-1 at 0.2 A g-1 and maintains 97% capacity after 500 cycles at 0.5 A g-1, outperforming larger-pored (10 nm) and non-porous variants. This research highlights a scalable strategy for designing mesoporous materials that optimize ion transport and structural stability, essential for advancing next-generation high-performance energy storage solutions.
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Halide perovskite, renowned for its multifunctional properties, shows considerable promise for realizing self-charging power systems. In this study, a lead-free methylammonium bismuth iodide (MA3Bi2I9) perovskite is used to create a self-charging power unit (SPU). This involves constructing a hybrid piezoelectric-triboelectric nanogenerator (Hybrid-TENG) and utilizing MA3Bi2I9 for energy storage as an anode in a lithium-ion battery (LIB). Initially, MA3Bi2I9 nanorods are synthesized and composited with a polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene polymer. The dielectric and mechanical properties of composite films having perovskite loading content are investigated. The optimized Hybrid-TENG exhibits superior performance, generating a voltage of 537 V, current density of 13.2 µA cm- 2, and maximum power density of 3.04 mW cm-2, which can be attributed to the high piezoelectric coefficient of MA3Bi2I9 nanorods (≈20.6 pm V-1). A MA3Bi2I9 thin film, serving as an electrode in LIB, demonstrates a high specific capacity of 2378.9 mAh cm-3 (578.8 mAh g-1) with a capacity retention of ≈87.5% over 100 cycles, underscoring its stable performance. Furthermore, a Hybrid-TENG is employed to charge the MA3Bi2I9-based LIB, thus realizing an SPU for driving portable electronics. This study highlights the promising potential of perovskites for developing efficient nanogenerators and LIBs, paving the way for sustainable energy solutions in small-scale electronics.
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Because of its high specific capacity and superior rate performance, porous carbon is regarded as a potential anode material for lithium-ion batteries (LIBs). However, porous carbon materials with wide pore diameter distributions suffer from low structural stability and low electrical conductivity during the application process. During this study, the calcium carbonate nanoparticle template method is used to prepare coal tar pitch-derived porous carbon (CTP-X). The coal tar pitch-derived porous carbon has a well-developed macroporous-mesoporous-microporous hierarchical porous network structure, which provides abundant active sites for Li+ storage, significantly reduces polarization and charge transfer resistance, shortens the diffusion path and promotes the rapid transport of Li+. More specifically, the CTP-2 anode shows high charge capacity (496.9â mAh g-1 at 50â mA g-1), excellent rate performance (413.6â mAh g-1 even at 500â mA g-1), and high cycling stability (capacity retention rate of about 100 % after 1,000 cycles at 2â A g-1). The clean and eco-friendly large-scale utilization of coal tar pitch will facilitate the development of high-performance anodes in the field of LIBs.
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This study presents an oxalic acid-assisted method for synthesizing spinel-structured lithium titanate (Li4Ti5O12; LTO)/carbon composite materials. The Ag-doped LTO nanoparticles (NPs) are synthesized via flame spray pyrolysis (FSP). The synthesized material is used as a precursor for synthesizing the LTO-NP/C composite material with chitosan as a carbon source and oxalic acid as an additive. Oxalic acid improves the dissolution of chitosan in water as well as changes the composition and physical and chemical properties of the synthesized LTO-NP/C composite material. The oxalic acid/chitosan ratio can be optimized to improve the electrochemical performance of the LTO-NP/C composite material, and the electrode synthesized with a high mass loading ratio (5.44 mg cm-2) exhibits specific discharge capacities of 156.5 and 136 mAh g-1at 0.05 C- and 10 C-rate currents, respectively. Moreover, the synthesized composite LTO-NP/C composite material exhibits good cycling stability, and only 1.7% decrease in its specific capacity was observed after 200 charging-discharging cycles at 10 C-rate discharging current.
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Li-ion batteries are expected to become the mainstream devices for green energy storage or power supply in the future due to their advantages of high energy and power density and long cycle life. Monitoring the temperature and strain change characteristics of Li-ion batteries during operation is conducive to judging their safety performance. The hinged differential lever sensitization structure was used for strain sensitization in the design of an FBG sensor, which also allowed the simultaneous measurement of strain and temperature. The temperature and strain variation characteristics on the surface of a Li-ion soft-packed battery were measured using the des.igned sensor. This report found that the charging and discharging processes of Li-ion batteries are both exothermic processes, and exothermic heat release is greater when discharging than when charging. The strain on the surface of Li-ion batteries depends on electrochemical changes and thermal expansion effects during the charge and discharge processes. The charging process showed an increasing strain, and the discharging process showed a decreasing strain. Thermal expansion was found to be the primary cause of strain at high rates.
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Nowadays, owing to the new technological and industrial requirements for equipment, such as flexibility or multifunctionally, the development of all-solid-state supercapacitors and Li-ion batteries has become a goal for researchers. For these purposes, the composite material approach has been widely proposed due to the promising features of woven carbon fiber as a substrate material for this type of material. Carbon fiber displays excellent mechanical properties, flexibility, and high electrical conductivity, allowing it to act as a substrate and a collector at the same time. However, carbon fiber's energy-storage capability is limited. Several coatings have been proposed for this, with nanostructured transition metal oxides being one of the most popular due to their high theoretical capacity and surface area. In this overview, the main techniques used to achieve these coatings-such as solvothermal synthesis, MOF-derived obtention, and electrochemical deposition-are summarized, as well as the main strategies for alleviating the low electrical conductivity of transition metal oxides, which is the main drawback of these materials.
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Fibra de Carbono , Capacidad Eléctrica , Suministros de Energía Eléctrica , Electrodos , Litio , Nanoestructuras , Óxidos , Litio/química , Fibra de Carbono/química , Óxidos/química , Nanoestructuras/química , Elementos de Transición/química , Conductividad Eléctrica , Metales/químicaRESUMEN
State-of-the-art Li batteries suffer from serious safety hazards caused by the reactivity of lithium and the flammable nature of liquid electrolytes. This work develops highly efficient solid-state electrolytes consisting of imidazolium-containing polyionic liquids (PILs) and lithium bis(trifluoromethane sulfonyl)imide (LiTFSI). By employing PIL/LiTFSI electrolyte membranes blended with poly(propylene carbonate) (PPC), we addressed the problem of combining ionic conductivity and mechanical properties in one material. It was found that PPC acts as a mechanically reinforcing component that does not reduce but even enhances the ionic conductivity. While pure PILs are liquids, the tricomponent PPC/PIL/LiTFSI blends are rubber-like materials with a Young's modulus in the range of 100 MPa. The high mechanical strength of the material enables fabrication of mechanically robust free-standing membranes. The tricomponent PPC/PIL/LiTFSI membranes have an ionic conductivity of 10-6 S·cm-1 at room temperature, exhibiting conductivity that is two orders of magnitude greater than bicomponent PPC/LiTFSI membranes. At 60 °C, the conductivity of PPC/PIL/LiTFSI membranes increases to 10-5 S·cm-1 and further increases to 10-3 S·cm-1 in the presence of plasticizers. Cyclic voltammetry measurements reveal good electrochemical stability of the tricomponent PIL/PPC/LiTFSI membrane that potentially ranges from 0 to 4.5 V vs. Li/Li+. The mechanically reinforced membranes developed in this work are promising electrolytes for potential applications in solid-state batteries.
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Líquidos Iónicos , Propano/análogos & derivados , Litio , Electrólitos , Iones , Poli A , PolímerosRESUMEN
Exploiting novel materials with high specific capacities is crucial for the progress of advanced energy storage devices. Intentionally constructing functional heterostructures based on a variety of two-dimensional (2D) substances proves to be an extremely efficient method for capitalizing on the shared benefits of these materials. By elaborately designing the structure, a greatly escalated steadiness can be achieved throughout electrochemical cycles, along with boosted electron transfer kinetics. In this study, chemical vapor deposition (CVD) was utilized to alter the surface composition of multilayer Ti3C2Tx MXene, contributing to contriving various layered heterostructure materials through a precise adjustment of the reaction temperature. The optimal composite materials at a reaction temperature of 500 °C (defined as MX500), incorporating MXene as the conductive substrate, exhibited outstanding stability and high coulombic efficiency during electrochemical cycling. Meanwhile, the reactive sites are increased by using TiS2 and TiO2 at the heterogeneous interfaces, which sustains a specific capacity of 449 mAh g-1 after 200 cycles at a current density of 0.1 A g-1 and further demonstrates their exceptional electrochemical characteristics. Additionally, the noted pseudocapacitive properties, like MXene materials, further highlight the diverse capabilities of intuitive material design. This study illuminates the complex details of surface modification in multilayer MXene and offers a crucial understanding of the strategic creation of heterostructures, significantly impacting sophisticated electrochemical applications.
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Covalent organic frameworks (COFs) have emerged as promising renewable electrode materials for LIBs and gained significant attention, but their capacity has been limited by the densely packed 2D layer structures, low active site availability, and poor electronic conductivity. Combining COFs with high-conductivity MXenes is an effective strategy to enhance their electrochemical performance. Nevertheless, simply gluing them without conformal growth and covalent linkage restricts the number of redox-active sites and the structural stability of the composite. Therefore, in this study, a covalently assembled 3D COF on Ti3C2 MXenes (Ti3C2@COF) is synthesized and serves as an ultralong cycling electrode material for LIBs. Due to the covalent bonding between the COF and Ti3C2, the Ti3C2@COF composite exhibits excellent stability, good conductivity, and a unique 3D cavity structure that enables stable Li+ storage and rapid ion transport. As a result, the Ti3C2-supported 3D COF nanosheets deliver a high specific capacity of 490 mAh g-1 at 0.1 A g-1, along with an ultralong cyclability of 10,000 cycles at 1 A g-1. This work may inspire a wide range of 3D COF designs for high-performance electrode materials.
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MnO has attracted much attention as the anode for Li-ion batteries (LIBs) owing to its high specific capacity. However, the low conductivity limited its large application. An effective solution to solve this problem is carbon coating. Biomass carbon materials have aroused much interest for being low-cost and rich in functional groups and hetero atoms. This work designs porous N-containing MnO composites based on the chemical-activated tremella using a self-templated method. The tremella, after activation, could offer more active sites for carbon to coordinate with the Mn ions. And the as-prepared composites could also inherit the special porous nanostructures of the tremella, which is beneficial for Li+ transfer. Moreover, the pyrrolic/pyridinic N from the tremella can further improve the conductivity and the electrolyte wettability of the composites. Finally, the composites show a high reversible specific capacity of 1000 mAh g-1 with 98% capacity retention after 200 cycles at 100 mA g-1. They also displayed excellent long-cycle performance with 99% capacity retention (relative to the capacity second cycle) after long 1000 cycles under high current density, which is higher than in most reported transition metal oxide anodes. Above all, this study put forward an efficient and convenient strategy based on the low-cost biomass to construct N-containing porous composite anodes with a fast Li+ diffusion rate, high electronic conductivity, and outstanding structure stability.
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High-voltage ultrahigh-Ni cathodes (LiNixCoyMn1-x-yO2, x≥0.9) can significantly enhance the energy density and cost-effectiveness of Li-ion batteries beyond current levels. However, severe Li-Ni antisite defects and their undetermined dynamic evolutions during high-voltage cycling limit the further development of these ultrahigh-Ni cathodes. In this study, we quantify the dynamic evolutions of the Li-Ni antisite defect using operando neutron diffraction and reveal its coupling relationship with anionic redox, another critical challenge restricting ultrahigh-Ni cathodes. We detect a clear Ni migration coupled with an unstable oxygen lattice, which accompanies the oxidation of oxygen anions at high voltages. Based on these findings, we propose that minimized Li-Ni antisite defects and controlled Ni migrations are essential for achieving stable high-voltage cycling structures in ultrahigh-Ni cathodes. This is further demonstrated by the optimized ultrahigh-Ni cathode, where reduced dynamic evolutions of the Li-Ni antisite defect effectively inhibit the anionic redox, enhancing the 4.5â V cycling stability.
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The pursuit of carbon-neutral energy has intensified the interest in green hydrogen production from direct seawater electrolysis, given the scarcity of freshwater resources. While Ni-based catalysts are known for their robust activity in alkaline water oxidation, their catalytic sites are prone to rapid degradation in the chlorine-rich environments of seawater, leading to limited operation time. Herein, we report a Ni(OH)2 catalyst interfaced with laser-ablated LiFePO4 (Ni(OH)2/L-LFP), derived from spent Li-ion batteries (LIBs), as an effective and stable electrocatalyst for direct seawater oxidation. Our comprehensive analyses reveal that the PO4 3- species, formed around L-LFP, effectively repels Cl- ions during seawater oxidation, mitigating corrosion. Simultaneously, the interface between in situ generated NiOOH and Fe3(PO4)2 enhances OH- adsorption and electron transfer during the oxygen evolution reaction. This synergistic effect leads to a low overpotential of 237â mV to attain a current density of 10â mA cm-2 and remarkable durability, with only a 3.3 % activity loss after 600â h at 100â mA cm-2 in alkaline seawater. Our findings present a viable strategy for repurposing spent LIBs into high-performance catalysts for sustainable seawater electrolysis, contributing to the advancement of green hydrogen production technologies.
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Compensating the irreversible loss of limited active lithium (Li) is essentially important for improving the energy-density and cycle-life of practical Li-ion battery full-cell, especially after employing high-capacity but low initial coulombic efficiency anode candidates. Introducing prelithiation agent can provide additional Li source for such compensation. Herein, we precisely implant trace Co (extracted from transition metal oxide) into the Li site of Li2 O, obtaining (Li0.66 Co0.11 â¡0.23 )2 O (CLO) cathode prelithiation agent. The synergistic formation of Li vacancies and Co-derived catalysis efficiently enhance the inherent conductivity and weaken the Li-O interaction of Li2 O, which facilitates its anionic oxidation to peroxo/superoxo species and gaseous O2 , achieving 1642.7â mAh/g~Li2O prelithiation capacity (≈980â mAh/g for prelithiation agent). Coupled 6.5â wt % CLO-based prelithiation agent with LiCoO2 cathode, substantial additional Li source stored within CLO is efficiently released to compensate the Li consumption on the SiO/C anode, achieving 270â Wh/kg pouch-type full-cell with 92 % capacity retention after 1000 cycles.