Search Results (88)

Na₄Fe₃(PO₄)₂P₂O₇ (NFPP) is recognized as a prospective electrode for sodium-ion batteries (SIBs) because of its structure stability, economic viability and environmental friendliness. Nevertheless, its commercialization is constrained by low operating voltage and limited theoretical capacity, which result in a power density significantly inferior to that of LiFePO₄. To address these limitations, in this work, we first designed and synthesized a series of Mn-doped NFPP to enhance its operating voltage, inspired by the successful design of LiFe_1-xMn_xPO₄ cathodes. This approach was implemented to enhance the operating voltage of the material. Subsequently, the optimized Na₄Fe_1.2Mn_1.8(PO₄)₂P₂O₇ (1.8Mn-NFMPP) sample was selected for further Ti-doped modification to enhance its cycle durability and rate performance. The final Mn/Ti co-doped Na₄Fe_1.2Mn_1.7Ti_0.1(PO₄)₂P₂O₇ (0.1Ti-NFMTPP) material exhibited a high operating voltage of ~3.6 V (vs. Na⁺/Na) in a half cell, with an outstanding reversible capacity of 122.9 mAh g⁻¹ at 0.1 C and remained at 90.6% capacity retention after 100 cycles at 0.5 C. When assembled into a coin-type full cell employing a commercial hard carbon anode, the optimized cathode material exhibited an initial capacity of 101.7 mAh g⁻¹, retaining 86.9% capacity retention over 50 cycles at 0.1 C. These results illustrated that optimal Mn/Ti co-doping is an effective methodology to boost the electrochemical behavior of NFPP materials, achieving mitigation of the Jahn–Teller effect on the Mn³⁺ and Mn dissolution problem, thereby significantly improving structural stability and cycling performance. Full article

Multilayer ceramic lithium batteries (MLCBs) are regarded as a new type of oxide-based all-solid-state microbattery for integrated circuits and various wearable devices. The chemical compatibility between the solid electrolyte and electrode active materials during the high-temperature co-sintering process is crucial for determining the structural stability and cycling performance of MLCBs. This study focuses on the typical MLCB composite electrodes composed of the NASICON-type Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) solid electrolyte and the spinel-type Li₄Ti₅O₁₂ (LTO) anode material. The thermal behavior, phase structure, morphological evolution, and elemental chemical states of these composite electrodes were systematically investigated over a co-sintering temperature range of 400–900 °C. The results indicate that the reactivity between LATP and LTO during co-sintering is primarily driven by the diffusion of Li from the LTO anode, leading to the formation of TiO₂, Li₃PO₄, and LiTiOPO₄. Furthermore, the co-sintered LATP-LTO multilayer composites reveal that the generation of Li₃PO₄ at the LATP/LTO interface facilitates their co-sintering integration at 800–900 °C, which is essential for the successful fabrication of MLCBs. These findings provide direct evidence and valuable references for the structural and performance optimization of MLCBs in the future. Full article

Solid-state lithium batteries are considered ideal due to the safety of solid-state electrolytes. The Na superionic conductor-type Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) is a solid electrolyte with high ionic conductivity, low cost, and stability. However, LATP is reduced upon contact with metallic lithium, leading to lithium dendrite growth on the anode during charging. In this study, LATP was synthesized, and the relationship between crystallinity and ionic conductivity was investigated at different heat treatment temperatures. Optimal sintering conditions and ionic conductivity were analyzed for sintering temperatures from 800 to 1000 °C. To suppress reactions with Li metal, 50 nm thick Ag and 10 nm thick Al₂O₃ layers were deposited on LATP via DC sputtering and plasma-enhanced atomic layer deposition. The electrochemical stability was tested under three conditions: uncoated LATP, Al₂O₃-coated LATP, and Ag+Al₂O₃-coated LATP. The stability improved in the following order: uncoated < Al₂O₃-coated < Ag+Al₂O₃-coated. The Al₂O₃ coating suppressed secondary phase formation by preventing direct contact between LATP and Li, while Ag coating mitigated charge concentration, inhibiting dendrite growth. These findings demonstrate that Ag and Al₂O₃ nano-layers enhance electrolyte stability, advancing solid-state battery reliability and commercialization. Full article

The impetus to study and develop polymer electrolytes for metal-ion batteries is due to their enhanced safety compared to flammable organic liquid electrolytes, promising ionic conductivity, and broad electrochemical stability window, making them to viable candidates for battery application. In the current work, we present a simple fabrication procedure and a comprehensive physico–chemical study of various PVDF-HFP-based electrolyte formulations with a sufficient addition of PEO polymer, LiTFSI conducting salt, and EMIMTFSI ionic liquid. The ionic conductivity, activation energy for ionic movement and thickness of the resulting polymer electrolyte show a non-linear dependency on the PVDF-HFP/PEO ratio. The electrolyte composition with a 0.35PEO-0.65PVDF-HFP/1LiTFSI/1EMIMTFSI mass fraction exhibits the highest ionic conductivity among the compositions, revealing $7.7\times {10}^{-5} \mathrm{S} {\mathrm{c}\mathrm{m}}^{-1}$ at 30 °C. Electrochemical tests in half full and full Li-ion batteries with a LiFePO₄ cathode and Li₄Ti₅O₁₂ anode also emphasized this composition as the most promising one, providing an initial capacity in full cells of 120 mAh g⁻¹ and a capacity retention of about 75% after 50 charge/discharge cycles at a 0.1 C current rate. In the PEO/PVDF-HFP polymer blend with EMIMTFSI as a plasticizer, the amount of crystalline parts, which are detrimental to a fast ionic diffusion, is significantly reduced. Full article

The recycling of lithium-ion batteries is increasingly important for both resource recovery and environmental protection. However, the complex composition of cathode and anode materials in these batteries makes the efficient separation of metal mixtures challenging. Hydrometallurgical methods, particularly liquid extraction, provide an effective means of separating metal ions, though they require periodic updates to their extraction systems. This study introduces a hydrophobic deep eutectic solvent composed of trioctylphosphine oxide, di(2-ethylhexyl)phosphoric acid, and menthol, which is effective for separating Ti(IV), Co(II), Mn(II), Ni(II), and Li⁺ ions from hydrochloric acid leachates of NMC (LiNi_xMn_yCo_1−x−yO₂) batteries with LTO (Li₄Ti₅O₁₂) anodes. By optimising the molar composition of the trioctylphosphine oxide/di(2-ethylhexyl)phosphoric acid/menthol mixture to a 4:1:5 ratio, high extraction efficiency was achieved. The solvent demonstrated stability over 10 cycles, and conditions for its regeneration were successfully established. At room temperature, the DES exhibited a density of 0.89 g/mL and a viscosity of 56 mPa·s, which are suitable for laboratory-scale extraction processes. Experimental results from a laboratory setup with mixer-settlers confirmed the efficiency of separating Ti(IV) and Co(II) ions in the context of their extraction kinetics. Full article

With the increasing demand for renewable energy and sustainable technologies, lithium-ion batteries (LIBs) have become crucial energy storage components. Despite the promising properties of the high capacity and stability of TiO₂, its large-scale application as an anode for LIBs is hindered by challenges like poor conductivity and volumetric changes during cycling. Here, a rutile TiO₂ composite material with a thinned carbon coating (TiO₂@TC) was synthesized through chemical vapor deposition (CVD) and a subsequent annealing process, which significantly improved the reversibility, cycling stability, and rate performance of the TiO₂ anode materials. The thickness of the carbon layer on TiO₂ was precisely controlled and thinned from 4.2 nm to 1.9 nm after secondary annealing treatment, leading to a smaller steric hindrance and an improved conductivity while serving as protective coatings by preventing the electrochemical degradation of the TiO₂ surface and hindering volumetric changes during cycling. The resulting TiO₂@TC with the thin carbon layer demonstrated a high specific capacity of 167 mAh g⁻¹ at 0.5 C in Li-based half cells, which could stably run for 200 cycles with nearly 100% capacity retention. The thin carbon layer also contributes to an improved rate performance of 90 mAh g⁻¹ at even 20 C. This work provides an innovational strategy for improving the conductivity and volumetric changes during the cycling of TiO₂ anodes. Full article

The popularization of lithium metal anode has been limited due to uneven deposition processes and lithium dendrites. Guiding homogeneous nucleation during the initial plating stage of lithium is vital to obtain a stable lithium metal anode. Herein, an ultra-thin dipole layer that can be used to regulate the diffusion layer is prepared by anodizing and strong polarization on a titanium foil collector. It is demonstrated that the vertical distributions of ionic concentration and electrostatic potential on the nBTO@Ti electrode are modulated by the ultrathin dipole layer, leading to uniform diffusion of lithium ions and reduction of overpotential. Consequently, a uniform lithium nucleation and plating process are achieved on a polarized BaTiO₃ collector, which is verified by microscopy. The average coulombic efficiency of the deposition-dissolution process is as high as 98.3% for 300 cycles at 0.5 mA cm⁻². Moreover, the symmetrical cell shows flat potential platforms of 25 mV for 1000 cycles at 0.5 mA cm⁻². Full cell with LiFePO₄ as cathode also reveals excellent electrochemical performances with a steady discharge capacity of 120 mAh g⁻¹ at 1 C and a high capacity retention of 93.3% after 200 cycles. Full article

Amidst the swift expansion of the electric vehicle industry, the imperative for alternative battery technologies that balance economic feasibility with sustainability has reached unprecedented importance. Herein, we utilized Perovskite-based oxide compounds barium titanate (BaTiO₃) and strontium titanate (SrTiO₃) nanoparticles as anode materials for lithium-ion batteries from straightforward and standard carbonate-based electrolyte with 10% fluoroethylene carbonate (FEC) additive [1M LiPF₆ (1:1 EC: DEC) + 10% FEC]. SrTiO₃ and BaTiO₃ electrodes can deliver a high specific capacity of 80 mA h g⁻¹ at a safe and low average working potential of ≈0.6 V vs. Li/Li⁺ with excellent high-rate performance with specific capacity of ~90 mA h g⁻¹ at low current density of 20 mA g⁻¹ and specific capacity of ~80 mA h g⁻¹ for over 500 cycles at high current density of 100 mA g⁻¹. Our findings pave the way for the direct utilization of perovskite-type materials as anode materials in Li-ion batteries due to their promising potential for Li⁺ ion storage. This investigation addresses the escalating market demands in a sustainable manner and opens avenues for the investigation of diverse perovskite oxides as advanced anodes for next-generation metal-ion batteries. Full article

Silicon (Si) has attracted worldwide attention for its ultrahigh theoretical storage capacity (4200 mA h g⁻¹), low mass density (2.33 g cm⁻³), low operating potential (0.4 V vs. Li/Li⁺), abundant reserves, environmentally benign nature, and low cost. It is a promising high-energy-density anode material for next-generation lithium-ion batteries (LIBs), offering a replacement for graphite anodes owing to the escalating energy demands in booming automobile and energy storage applications. Unfortunately, the commercialization of silicon anodes is stringently hindered by large volume expansion during lithiation–delithiation, the unstable and detrimental growth of electrode/electrolyte interface layers, sluggish Li-ion diffusion, poor rate performance, and inherently low ion/electron conductivity. These present major safety challenges lead to quick capacity degradation in LIBs. Herein, we present the synergistic effects of nanostructured silicon and SrTiO₃ (STO) for use as anodes in Li-ion batteries. Si and STO nanoparticles were incorporated into a multiwalled carbon nanotube (CNT) matrix using a planetary ball-milling process. The mechanical stress resulting from the expansion of Si was transferred via the CNT matrix to the STO. We discovered that the introduction of STO can improve the electrochemical performance of Si/CNT nanocomposite anodes. Experimental measurements and electrochemical impedance spectroscopy provide evidence for the enhanced mobility of Li-ions facilitated by STO. Hence, incorporating STO into the Si@CNT anode yields promising results, exhibiting a high initial Coulombic efficiency of approximately 85%, a reversible specific capacity of ~800 mA h g⁻¹ after 100 cycles at 100 mA g⁻¹, and a high-rate capability of 1400 mA g⁻¹ with a capacity of 800 mA h g⁻¹. Interestingly, it exhibits a capacity of 350 mAh g⁻¹ after 1000 lithiation and delithiation cycles at a high rate of 600 mA hg⁻¹. This result unveils and sheds light on the design of a scalable method for manufacturing Si anodes for next-generation LIBs. Full article

Antimony (Sb) and its composites have been recognized as potentially good anode materials for lithium-ion batteries (LIBs) due to their relatively high theoretical capacity of 660 mAh g⁻¹ and to their low cost. However, Sb-based anodes suffer from a high-volume change during the lithiation/delithiation process that results in capacity fading and anode degradation after prolonged charge/discharge cycles. To address this issue, Sb₂O₃/TiO₂ nanocomposite electrodes can be synthesized and used as anodes for LIBs with high capacity and good electrochemical stability. In the present work, TiO₂@Sb₂O₃ composites with different (TiO₂:Sb₂O₃) ratios of 0:1, 1:1, 1:4 and 3:1 were synthesized and directly used as anode materials for LIBs. The electrochemical performance of the TiO₂/Sb₂O₃ composite anode with different ratios of TiO₂ to Sb₂O₃ was evaluated by galvanostatic charge/discharge, rate performance and cyclic voltammetry. The 3:1 (TiO₂:Sb₂O₃) composite anode delivered the highest capacity compared to those of the TiO₂, SbO₃, 1:1 (TiO₂:Sb₂O₃) and 1:4 (TiO₂:Sb₂O₃) electrodes. The TiO₂@Sb₂O₃ composite anode with a 3:1 ratio exhibited a stabilized capacity of 536 mAh g⁻¹ after 100 cycles at 100 mA g⁻¹ and showed excellent rate performance, with current densities between 50 and 500 mA g⁻¹. The improved electrochemical performance was attributed to the synergistic effect of TiO₂ (i.e., the coating of Sb₂O₃ with TiO₂) on reducing the volume change of the Sb anode material after prolonged charge/discharge cycles and on maintaining a stable interface between the electrolyte and the composite electrode material. Full article

Phosphorus (P) and TiO₂ have been extensively studied as anode materials for lithium-ion batteries (LIBs) due to their high specific capacities. However, P is limited by low electrical conductivity and significant volume changes during charge and discharge cycles, while TiO₂ is hindered by low electrical conductivity and slow Li-ion diffusion. To address these issues, we synthesized organic–inorganic hybrid anode materials of P–polypyrrole (PPy) and TiO₂–PPy, through in situ polymerization of pyrrole monomer in the presence of the nanoscale inorganic materials. These hybrid anode materials showed higher cycling stability and capacity compared to pure P and TiO₂. The enhancements are attributed to the electrical conductivity and flexibility of PPy polymers, which improve the conductivity of the anode materials and effectively buffer volume changes to sustain structural integrity during the charge and discharge processes. Additionally, PPy can undergo polymerization to form multi-component composites for anode materials. In this study, we successfully synthesized a ternary composite anode material, P–TiO₂–PPy, achieving a capacity of up to 1763 mAh/g over 1000 cycles. Full article

The present article introduces a strategy for controlling oxidation and reduction reactions within polymer electrolyte membrane (PEM) networks as a means of enhancing storage capacity through the complexation of dissociated lithium cations with multifunctional groups of the polymer network. Specifically, co-polymer networks based on polysulfide (PS) and polyoxide (PO) precursors, photo-cured in the presence of succinonitrile (SCN) and lithium bis(trifluoro methane sulfonyl imide) (LiTFSI) salt, exhibited ionic conductivity on the order of mid 10⁻⁴ S/cm at ambient temperature in the 30/35/35 (weight %) composition. Lithium titanate (LTO, Li₄Ti₅O₁₂) electrode was chosen as an anode (i.e., a potential source of Li ions) against lithium iron phosphate (LFP, LiFePO₄) cathode in conjunction with polysulfide-co-polyoxide dual polyelectrolyte networks to control viscosity for 3D printability on conformal surfaces of drone and aeronautic vehicles. It was found that the PS-co-PO dual network-based polymer electrolyte containing SCN plasticizer and LiTFSI salt exhibited extra storage capacity (i.e., specific capacity of 44 mAh/g) with the overall specific capacity of 170 mAh/g (i.e., for the combined LTO electrode and PEM) initially that stabilized at 153 mAh/g after 50th cycles with a reasonable capacity retention of over 90% and Coulombic efficiency of over 99%. Of particular interest is the observation of the improved electrochemical performance of the polysulfide-co-polyoxide electrolyte dual-network relative to that of the polyoxide electrolyte single-network. Full article

This study reports five types of metal-doped (Co, Cu, Sn, V, and Zr) NASICON-type Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP)/polymer composite solid electrolytes (CSEs) enabling Li₄Ti₅O₁₂ (LTO) anodes to have high rate capability and excellent cycling performance. The high Li⁺-conductivity LATP samples are successfully synthesized through a modified sol–gel method followed by thermal calcination. We find that the cation dopants clearly influence the substitution of Al for Ti, with the type of dopant serving as a crucial factor in determining the ionic conductivity and interfacial resistance of the solid electrolyte. The CSE containing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and Sn-LATP shows an ionic conductivity of 1.88 × 10⁻⁴ S cm⁻¹ at ambient temperature. The optimum conductivity can be attributed to alterations in the lattice parameters and Li⁺ transport pathways owing to Sn doping. The solid-state cell equipped with the LTO-supported CSE containing Sn-LATP fillers demonstrates both excellent high rate capability at 5 C (with a capacity retention of 86% compared to the value measured at 0.2 C) and superior cycling stability, maintaining high Coulombic efficiency (>99.0%) over 510 cycles. These findings indicate that the proposed CSE is highly promising for use in solid-state lithium batteries with desirable charge–discharge properties and high durability. Full article

Broad adoption has already been started of MXene materials in various energy storage technologies, such as super-capacitors and batteries, due to the increasing versatility of the preparation methods, as well as the ongoing discovery of new members. The essential requirements for an excellent anode material for lithium-ion batteries (LIBs) are high safety, minimal volume expansion during the lithiation/de-lithiation process, high cyclic stability, and high Li⁺ storage capability. However, most of the anode materials for LIBs, such as graphite, SnO₂, Si, Al, and Li₄Ti₅O₁₂, have at least one issue. Hence, creating novel anode materials continues to be difficult. To date, a few MXenes have been investigated experimentally as anodes of LIBs due to their distinct active voltage windows, large power capabilities, and longer cyclic life. The objective of this review paper is to provide an overview of the synthesis and characterization characteristics of the MXenes as anode materials of LIBs, including their discharge/charge capacity, rate performance, and cycle ability. In addition, a summary of the potential outlook for developments of these materials as anodes is provided. Full article

The most popular anode material in commercial Li-ion batteries is still graphite. However, its low intercalation potential is close to that of lithium, which results in the dendritic growth of lithium at its surface, and the formation of a passivation film that limits the rate capability and may result in safety hazards. High-performance anodes are thus needed. In this context, lithium titanite oxide (LTO) has attracted attention as this anode material has important advantages. Due to its higher lithium intercalation potential (1.55 V vs. Li⁺/Li), the dendritic deposition of lithium is avoided, and the safety is increased. In addition, LTO is a zero-strain material, as the volume change upon lithiation-delithiation is negligible, which increases the cycle life of the battery. Finally, the diffusion coefficient of Li⁺ in LTO (2 × 10⁻⁸ cm² s⁻¹) is larger than in graphite, which, added to the fact that the dendritic effect is avoided, increases importantly the rate capability. The LTO anode has two drawbacks. The energy density of the cells equipped with LTO anode is lower compared with the same cells with graphite anode, because the capacity of LTO is limited to 175 mAh g⁻¹, and because of the higher redox potential. The main drawback, however, is the low electrical conductivity (10⁻¹³ S cm⁻¹) and ionic conductivity (10⁻¹³–10⁻⁹ cm² s⁻¹). Different strategies have been used to address this drawback: nano-structuration of LTO to reduce the path of Li⁺ ions and electrons inside LTO, ion doping, and incorporation of conductive nanomaterials. The synthesis of LTO with the appropriate structure and the optimized doping and the synthesis of composites incorporating conductive materials is thus the key to achieving high-rate capability. That is why a variety of synthesis recipes have been published on the LTO-based anodes. The progress in the synthesis of LTO-based anodes in recent years is such that LTO is now considered a substitute for graphite in lithium-ion batteries for many applications, including electric cars and energy storage to solve intermittence problems of wind mills and photovoltaic plants. In this review, we examine the different techniques performed to fabricate LTO nanostructures. Details of the synthesis recipes and their relation to electrochemical performance are reported, allowing the extraction of the most powerful synthesis processes in relation to the recent experimental results. Full article