Pros and cons of wood cellulose binders for 4.6V LiCoO2 lithium-ion batteries.

Near-surface solid electrolyte modification of single-crystal high-nickel cathode materials for high performance lithium-ion batteries

Attributes of biomass-derived carbon from natural commercial sponge and its application as a high-performance anode material for lithium-ion batteries

ABSTRACT Lithium-group IV (Li-Si, Li-Ge, Li-Sn) compounds are promising negative-electrode materials for lithium-ion batteries. Their mechanical properties and structural stability during lithiation are critical for practical applications. Despite numerous reports on Li-IV compounds with various stoichiometries, high-pressure experimental data remain limited, particularly for Li-Sn systems. In this study, synchrotron X-ray diffraction (XRD) measurements were performed on LiSn, Li₇Sn₂, Li₁₇Sn₄, LiGe, and Li₁₂Ge₇ under high pressure using a diamond anvil cell. The pressure dependence of unit-cell volume and bulk modulus was determined based on the Murnaghan equation of state. No pressure-induced structural phase transitions were identified up to 10–30 GPa for all compounds investigated. A monotonic decrease in the bulk modulus with increasing Li fraction was commonly observed across Li-Sn, Li-Ge, and Li-Si systems. Structural trends across the Li-group IV systems are discussed in comparison with theoretical predictions and reported data.

LiFePO4 is particularly popular as a positive electrode material for lithium-ion batteries owing to the natural abundance of Fe. However, the phase transformations of LiFePO4 and the resulting increase in its rate capability are insufficiently understood. Herein, we employed almost simultaneous operando X-ray diffraction and X-ray absorption measurements combined with multivariate-curve resolution to re-explore the phase transformation between Li-rich (LFP) and Li-poor (FP) phases by focusing on the differences in the orthorhombic lattice parameters during charging and discharging at the same capacities (δao, δbo, and δco). At the low rate of 1/14 C (1 C is equal to one full charge for 1 h), all δ parameters remained approximately 0%, indicating a symmetric and isotropic phase transformation. By contrast, at a moderate rate of 5/14 C, δao and δbo for the LFP phase had opposite signs with values of -0.05% and +0.1%, respectively, whereas those for the FP phase were almost 0%. These results indicate that the anisotropic and asymmetric strains generated in the LFP phase solely contribute to the high rate capability. The δ parameter thus provides a quantitative and comparable framework for evaluating the phase transformation behavior in LiFePO4 and can be extended to other solid-state ionic materials.

Silicon (Si) has emerged as one of the most promising anode materials for next-generation lithium-ion batteries (LIBs) due to its extremely high theoretical capacity (3579 mAh g-1), abundant reserves, and inherent safety advantages over conventional graphite anodes. However, the practical application of Si anodes remains hampered by key challenges, including severe volume expansion (∼300%), an unstable solid electrolyte interface (SEI), low intrinsic conductivity, and irreversible capacity loss. Academia and industry have invested significant effort in addressing these issues through nanoscale structural engineering, Si-carbon composites, advanced polymer and inorganic binders, artificial SEI coatings, and electrolyte/interface design. Simultaneously, industry has begun to adopt scalable strategies, such as graphite-Si composite hybrids, surface encapsulation, prelithiation, and the integration of fluorinated additives and locally high electrolyte concentrations, to extend cycle life and improve manufacturability. This review focuses on the fundamental mechanisms of Si anodes, summarizes the latest research strategies from both laboratory and industrial perspectives, and explores commercialization pathways through case studies of emerging technologies and global investment. Finally, we outline future research directions and prospects for silicon anodes in advanced battery systems, emphasizing the need to balance performance, cost, and scalability. Silicon is not only a key transition material for high-energy lithium-ion batteries, but also an enabling platform for anode technologies in the post-lithium era.

Silicon oxycarbide (SiOC) is a promising anode material for lithium-ion batteries, yet its practical application is limited by low initial Coulombic efficiency (ICE), sluggish ion kinetics, and poor intrinsic electrical conductivity. Herein, SiMoOC-based ceramic nanocomposites derived from molybdenum-containing polysiloxane were prepared for lithium-ion storage. The molecular structure of the preceramic precursors and resulted chemical composition of the nanocomposites enable in situ formation of both Nowotny phase (Mo4.8Si3C0.6) and MoC nanocrystals within the SiOC matrix. The Mo4.8Si3C0.6/MoC/SiOC nanocomposites exhibit strongly enhanced electrochemical performance with the reversible capacity up to 883.59 mAh g-1, notably demonstrating an increased ICE from 67.7% to 75.9%, retaining a specific capacity of 455.2 mAh g-1 after 500 cycles at a high current density of 1 A g-1. The enhanced performance can be attributed to the Mo4.8Si3C0.6 and MoC nanocrystals with appropriate combination and microstructure: the highly conductive Mo4.8Si3C0.6 nanoparticles synergistically construct an efficient conductive network with ultrafine MoC nanocrystals, which not only contribute reversible capacity as active sites but also effectively regulate the solid electrolyte interphase (SEI). This unique microstructure comprehensively optimizes electrode reaction kinetics by constructing multidimensional lithium-ion transport pathways and enriching active sites, simultaneously achieving high specific capacity, high reaction reversibility, and long-term cycling stability.

Metal-organic frameworks (MOFs) have emerged as structurally designable materials for lithium-ion batteries (LIBs) due to their tunable coordination architecture and functionality. Herein, we report a couple of isostructural MOFs of divalent cobalt (1) and zinc (2), [MII2(bdc)2(DABCO)]n, [bdcH2 = terephthalic acid, DABCO = 1,4-diazabicyclo[2.2.2]octane], and evaluate their lithium storage performance. Electrochemical properties and performance show that Co-MOF 1 has higher efficiency than the Zn congener, with an excellent specific capacity of 750 mAh g-1 after 10 cycles and last at 322 mAh g-1 after 200 cycles, which is a high electrochemical performance in specific capacity and rate cycle performance over the previous MOF-based materials. The ligand substitution at the metal centers of the MOFs triggered the single-crystal to single-crystal transformation toward corresponding [MII(H2O)(bdc)(DABCO)]n (1a and 2a) MOFs, which were investigated. First-principles computations revealed that the identity of the metal center critically governs the lithiation behavior of these MOFs.

The rapid deployment of lithium-ion batteries has intensified the accumulation of end-of-life cells, posing both environmental risks and resource challenges. Conventional recycling routes largely rely on energy- and chemical-intensive metallurgical processes that downcycle electrode materials into low-value products. More recently, direct regeneration strategies have emerged to restore degraded electrodes; however, their ability to meet the performance demands of next-generation batteries remains limited. In this review, we present a defect-centric perspective on the upcycling of spent lithium-ion battery materials, reframing degradation-induced defects from liabilities into functional design assets. We analyze the hierarchical defect landscapes in aged electrodes, spanning atomic-scale vacancies, surface and subsurface lattice distortions, and particle-scale cracking and pulverization, and discuss how these intrinsic defects can be harnessed to enable targeted reconstruction through doping, compositional tuning, surface modification, and crystal-structure reconfiguration. By correlating defect characteristics with reconstruction pathways and electrochemical outcomes, we highlight emerging strategies that transform low-value waste materials into high-performance electrodes. Finally, we discuss key challenges associated with scalability, compositional control and performance consistency, and outline future directions for defect-driven upcycling toward a sustainable and circular battery economy.

Direct recycling is a promising approach for valorizing spent lithium-ion batteries, yet the effect of impurities on cathode regeneration has been insufficiently explored. Herein, an end-of-life LiNi0.6Co0.2Mn0.2O2 (NCM622) pouch cell is used as a model system to systematically investigate the behavior of impurities and the outcomes for regeneration, using XPS, SRD, and XAS techniques. The analysis identifies AlPO4, AlF3, Li3PO4, LiF, LixPFyO4, and Li2CO3 as the main impurities in the spent powder, along with Al-inclusion limited to a surface near region. Among these, Al- and F-containing species are found to significantly affect the regeneration process, inducing further Al- and F-inclusion in the regenerated material, while PO43- species exhibit a minimal structural impact. In-depth structural analysis reveals that F-inclusion proceeds via substitution of lattice oxygen, causing increased structural disorder. Al-inclusion most likely involves epitaxial crystal growth promoted by excess lithium salts, resulting in structural asymmetry at elevated inclusion levels. Electrochemical evaluation shows that low-level impurity inclusion has a negligible effect on initial capacity. Yet, impurity accumulation, potentially amplified over repeated recycling, markedly compromises capacity recovery and structural integrity. This work clarifies impurity-induced effects during regeneration and highlights the importance of impurity control for enabling sustainable and effective direct recycling.

Silicon oxide (SiOx) has emerged as one of the most promising anode materials for lithium-ion batteries due to its high theoretical capacity, ultralow lithiation/delithiation voltage, and abundant natural resource reserves. However, its severe volume expansion and insufficient cycling stability during lithiation-delithiation processes pose significant challenges to practical applications. Herein, an energy-dissipative sesbania gum-grafted-poly(acrylic acid) (SG-g-PAA) binder is fabricated via free-radical-initiated graft copolymerization for SiOx anodes. The SG-g-PAA binder rationally combines the intrinsic elasticity of the natural SG with the stiffness of PAA to construct a mechanically stable framework. The 3D network balances stiffness and elasticity, effectively accommodating the large volumetric changes while preserving electrode structural integrity during cycling. And the synergistic combination of covalent cross-links and dynamic hydrogen bonding further enhance the long-term cycling stability in SiOx anodes. With this binder, the SiOx electrode delivers a high specific capacity of 1134 mAh g-1 after 250 cycles at a current density of 400 mA g-1. The assembled SiOx@SG-g-PAA||NCM622 full cell showed an 88% capacity retention over 100 cycles at 0.3 C.

Manganese-based oxides are regarded as highly promising anode materials for lithium-ion batteries due to their high theoretical specific capacity, abundant resources, and environmental friendliness. This study aims to enhance the structural stability of manganese-based anodes during cycling by introducing structurally stable niobium oxide doping into manganese oxides. Using manganese dioxide (MnO2) and niobium pentoxide (Nb2O5) as raw materials, three sets of manganese-niobium composite oxide precursors with different molar ratios (namely Mn/Nb-10, Mn/Nb-20 and Mn/Nb-30) were prepared via high-energy ball milling and subsequently heat-treated at a uniform calcination temperature. Electrochemical testing revealed that among the three samples, the Mn/Nb-10 exhibited the most outstanding electrochemical performance: its reversible specific capacity remained at 1113.81 mAh·g-1 after 300 cycles, and it maintained a discharge specific capacity of 337.04 mAh·g-1 at the high current density of 1 A·g-1 after 500 cycles. More significantly, the incorporation of niobium markedly suppressed volume expansion during lithium-ion deintercalation, effectively mitigating electrode structural pulverization and capacity decay. This nanocomposite exhibits high reversible specific capacity, good rate capability, and stable cycling performance. It holds broad application prospects in high-energy-density lithium-ion battery systems and is expected to become an ideal candidate for next-generation high-performance anode materials.

Here, we report on a study of nickel germanate formation in the Ni(OH)2-GeO2 system under solid-phase synthesis conditions in the 500-800°C temperature range and on the research of electrochemical performance of Ni2GeO4-based electrodes. It is shown that the Ni2GeO4 formation occurred at temperatures around 700°C, and the process began with the melting of the nonautonomous phase GeO2 at Tm2n = 725 ± 112°C. The nickel germanate-based electrodes showed a rapid decrease in capacity over 40 cycles. However, starting from the 80th cycle, a gradual increase in capacity was observed from 190 to 528 mAh/g at the 270th cycle. We attribute this increase in capacity to evolution in the specific surface area and porosity of the electrode material during long-term cycling.

A deep learning model is employed to address the challenging problem of V 2 O 5 nanoparticle segmentation and the correlation between the chemical composition and the geometrical features of lithiated V 2 O 5 nanoparticles as an exemplar of a phase-transforming battery cathode material. First, the deep learning-enabled segmentation model is integrated with the singular value decomposition technique and a spectral database to generate accurate composition and phase maps capturing lithiation heterogeneities as imaged using scanning transmission X-ray microscopy. These phase maps act as the output properties for correlation analysis. Subsequently, the quantitative influences of the geometrical features of nanoparticles such as the particle size (i.e., projected perimeter and area), the aspect ratio, circularity, convexity, and orientation on the lithiation phase maps are revealed. These findings inform strategies to improve lithiation uniformity and reduce stress in phase-transforming lithium battery materials via optimized particle geometry. • Achieved nanoparticle segmentation in STXM data using a deep learning model. • Generated particle-wise lithiation composition maps from spectral deconvolution. • Revealed strong correlations between particle geometries and lithiation features. • Provided insights into electrode performance enhancement via structural design.

Titanium dioxide, or TiO₂, has garnered considerable attention as an anode material in lithium-ion batteries. Its inherent structural robustness, widespread availability, and inherent safety profile make it a promising candidate. Yet, its real-world utility is often hampered by relatively sluggish lithium diffusion kinetics and restricted electronic conductivity. Here, we delve into the impact of transition-metal doping, specifically iron (Fe), cobalt (Co), and manganese (Mn), on the lithium storage capabilities of anatase TiO₂. We leverage first-principles density functional theory (DFT) to investigate. A systematic analysis is conducted to examine the lithium adsorption characteristics, diffusion routes, charge redistribution phenomena, and electronic structure modifications that result from doping. Notably, our findings indicate that each of the doped configurations exhibits enhanced Li binding energies, reduced diffusion barriers, and narrower band gaps compared to unmodified TiO₂. Notably, Mn-doped TiO₂ exhibits the most favourable diffusion energy barrier (0.38 eV), a significant theoretical capacity (388 mAh/g), and substantial charge delocalisation. Furthermore, charge density difference (CDD) mappings corroborate the amplified charge transfer dynamics occurring between Li and the host lattice in the doped frameworks, particularly accentuated in the presence of Mn. These results suggest that the rational introduction of transition-metal dopants may represent a viable avenue for optimising TiO₂-based anodes geared toward advanced lithium-ion battery technologies.

Abstract The increasing demand for high-performance and sustainable lithium-ion batteries has led to the exploration of alternative anode materials beyond traditional graphite. Hard carbon, a disordered form of carbon characterized by expanded interlayer spacing and a high density of defect sites, exhibits promising electrochemical properties, particularly under fast-charging and low-temperature operation conditions. In this study, waste polyethylene terephthalate (PET) was converted into hard carbon anodes through pyrolysis at two different temperatures: 1000 °C and 1500 °C. The objective was to examine how the thermal treatment affects the structural characteristics and lithium ion storage behavior of the materials. X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) analyses indicated that the lower-temperature (1000 °C) heat-treated PET-derived hard carbon (pHC-L) had a more disordered structure with larger interlayer spacing and a higher concentration of defects. In contrast, the higher-temperature (1500 °C) heat-treated sample PET-derived hard carbon (pHC-H) showed increased graphitic ordering and fewer surface-active sites. At 20 mA g-1, the hard carbon produced at the lower heat-treatment temperature delivered 186.94 mAh g-1, compared with 130.15 mAh g-1 for the higher-temperature product; this improvement is attributed to the larger interlayer spacing and higher defect/micropore population, which promote sloping-type lithium-ion adsorption and pore-filling. Meanwhile, pHC-H demonstrated better rate performance with reduced polarization and enhanced reversibility. Both electrodes displayed a gradual increase in capacity during cycling, indicating structural activation attributed to solid-electrolyte interphase stabilization and improved accessibility of the electrolyte. These findings indicate that waste PET-derived hard carbon can be effectively optimized through pyrolysis temperature to achieve a balance between capacity and rate capability. This presents a sustainable and versatile platform for anode materials in next-generation lithium-ion batteries.

This study explores the use of organic compounds with triazole and thiophene units as anode materials in lithium-ion batteries (LIBs) for the first time in the literature. The triazole group, being electron-deficient, and the thiophene groups, electron-rich, form a donor-acceptor framework that enhances electron conductivity and storage capacity. The porous nature of these conjugated frameworks facilitates lithium-ion insertion and extraction, which is vital for reversible lithium storage. When combined with conductive carbon materials, the electrochemical performance of these organic compounds is significantly improved, with carbon enhancing electrical conductivity and ensuring adherence to current collectors. The initial discharge capacities of the organic compounds DTT1, DTT2, and DTT3 were 817 mAh g-1, 678 mAh g-1, and 915 mAh g-1, respectively, compared to the reference graphite electrode at 100 mA g-1. DTT3 exhibited superior initial capacity, rate performance, and cycling stability. After 100 cycles at a high current rate (1500 mA g-1), DTT3 showed the best retention capacity of 72%, outperforming DTT1 (72%), DTT2 (69%), and graphite (49%). These results demonstrate that organic materials, particularly DTT3, offer a promising alternative to conventional graphite anodes for high-performance LIBs.

Silicon (Si) is widely recognized as one of the most promising anode materials for next-generation lithium-ion batteries (LIBs). Nevertheless, its practical application is hindered by significant volume expansion and poor interfacial stability. Herein, a highly adhesive and ion-conductive polyimide binder, denoted as PIy, is synthesized via low-temperature self-catalyzed imidization through the copolymerization of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) with 2,2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) as the tough monomer, 4,4'-diamino-2,2'-bipyridyl (DAPY) as a base-catalyzing component, and 2-(5-amino-2-methylanilino)-4-(3-pyridyl)pyrimidine (AMPY) as an end-capping agent. DAPY and AMPY effectively lower the activation energy of poly(amic acid) imidization which enables cyclization to proceed at low temperatures and the pyridine groups promote Li+ transport. BPDA and BAPP contain abundant aromatic rings that provide high toughness and impart a high modulus to suppress volume changes. Meanwhile, the flexible -O- segments enhance chain mobility adapting to expansion while maintaining structural integrity. The Si@PIy-185°C electrode exhibits excellent long-term cycling stability, maintaining a high specific capacity of 1118.6mAhg- 1 at 1Ag- 1 even after 1000 cycles.The full cell of the SiOx@PIy-185°C//NCM811 exhibits a remarkable capacity retention of 87.8% after 100 cycles, highlighting the potential of the low-temperature imidized PI binder for high-energy-density LIBs.

Nickel-rich NMC-811 is a benchmark cathode material for high-energy density lithium-ion batteries due to its high specific capacity (>200 mAh g−1) and operating voltage (~3.8 V). However, its strong surface reactivity toward atmospheric species, particularly moisture and CO2, poses significant challenges during storage and processing, leading to the formation of LiOH- and Li2CO3-rich surface layers. Although the effects of humid air have been widely investigated, a direct comparison between high relative humidity and pure CO2 exposure remains limited. Here, we systematically examine the morphological, structural, chemical, and electrochemical evolution of commercial NMC-811 electrodes after 5 h exposure to 80% relative humidity or CO2-saturated atmosphere. Moisture treatment induces substantial surface reconstruction, lattice shrinkage, and increased cation disorder, accompanied by extensive hydroxide and carbonate formation. In contrast, CO2 exposure mainly modifies the outermost surface layer without significant bulk structural changes. Electrochemical testing reveals that CO2-treated electrodes display higher initial polarization but quickly recover near-pristine performance, whereas humidity-treated electrodes exhibit persistent kinetic limitations, accelerated capacity fading, and earlier end-of-life. Overall, degradation severity follows the trend: pristine < CO2 < RH 80%, highlighting the dominant role of moisture in irreversible structural deterioration.

Carbon dots (CDs), an emerging class of zero-dimensional carbon nanomaterials, have attracted extensive attention for lithium-based energy storage due to their high specific surface area, tunable surface chemistry, excellent electronic conductivity, and abundant, readily functionalized surface states. Recent advances have demonstrated that CDs can serve as conductive bridges, chemical regulators, and interfacial stabilizers across all key components of lithium batteries, enabling the simultaneous optimization of electronic and ionic transport, as well as interfacial reactions, in cathodes, anodes, and electrolytes. This review systematically summarizes the synthesis strategies and structural classifications of CDs, emphasizing how precursor selection, heteroatom doping, and surface functionalization determine their core-shell structures, defect states, and chemical reactivity. Subsequently, the applications of CDs in cathode modification, anode reinforcement, and electrolyte optimization are discussed in detail, highlighting their roles in enhancing charge-transfer kinetics, modulating ion transport, stabilizing interphases, and suppressing lithium dendrite formation. Special attention is given to interfacial reconstruction mechanisms driven by heteroatom-doped or functionalized CDs, which simultaneously promote ionic conduction and electron blocking at solid-solid interfaces. Finally, current challenges and future directions are outlined, including predictive synthesis design, interfacial chemistry optimization, multiscale composite construction, and scalable green fabrication. Overall, this review aims to deepen the understanding of CD-mediated interfacial engineering and to provide design guidelines for the development of safe, long-life, and high-energy-density lithium-based batteries.