Superior Lithium Research Articles

Polyacrylonitrile and aluminum metal dual functionalization interconnected network for superior lithium storage in silicon anode

Currently, silicon-based anode is one of the most promising anode materials that can be applied in next-generation lithium-ion batteries. However, the high activity of the electrode–electrolyte interface and low electronic conductivity of Si anode during the cycling process greatly limits its large-scale application. Aluminum (Al) is the metallic current collector known to promote electronic conductivity and lithium-ion transfer at low cost. However, to our knowledge, scalable interface engineering incorporating Al with carbonized polymer has not been reported. Herein, a polyacrylonitrile (PAN) and aluminum metal dual functionalization interconnected network is achieved via a simple sol-gel method followed by high-temperature calcination to obtain a stable solid electrolyte interphase (SEI) while allowing fast Li+ transmission. The calculated diffusion energy barrier for lithium ions in Al is 0.2198 eV, significantly lower than that in Cu and Fe. Benefiting from the enhanced interfacial protection and kinetics of Si with polyacrylonitrile/Al, the prepared Si@Al@CPAN anode exhibits high lithium storage capacity (2034.90 mAh/g after 150 cycles at 0.84 A/g). At the same time, the prepared Si@Al@CPAN anode outperforms the pure Si anode in rate performance at 12.6 A/g (1116.75 mAh/g vs. 2.84 mAh/g). The present work delivers new design ideas for high-performance Si anode with a multi-functionalization interface.

Iron-based bimetallic oxide carbon composites with superior lithium storage capabilities serve as anode in lithium-ion batteries

Transition metal oxides (TMOs) have emerged as highly promising electrode materials for lithium-ion batteries (LIBs) owing to their versatile valence states and distinctive morphological attributes. Bimetallic oxides, in particular, exhibit the ability to mitigate the volume expansion associated with lithium alloying and de-alloying processes. Despite these advantages, metal oxides often suffer from drawbacks such as poor conductivity, limited cycle stability, and a propensity for lithiation. Addressing the challenges of low electronic conductivity, significant volume expansion, and inadequate uniformity, we synthesized two bimetallic oxide-based carbon composites via a “one-pot” solvothermal approach: ZnFe2O4@C and MnFe2O4@C. These composites are enveloped in a carbon shell derived from anhydrous ethanol. Notably, the specific discharge capacities of ZnFe2O4@C and MnFe2O4@C surpass those of their respective single metal oxide counterparts. Following nearly 300 cycles of charge and discharge operations at a current density of 100 mA g−1, ZnFe2O4@C exhibited a specific discharge capacity of 1528 mAh g−1, while MnFe2O4@C demonstrated a capacity of 1283 mAh g−1. The synthesis method offers simplicity, high yield, and uniform morphology, making it a promising avenue for enhancing the performance of LIBs electrode materials.

In situ anchoring of FeNi nanoparticles into three-dimensional nitrogen-doped carbon framework as a self-supporting electrode for high-performance lithium storage

Constructing free-standing electrodes with superior lithium storage capacity and good mechanical performance are fascinating for next-generation lithium-ion batteries (LIBs). Nevertheless, their practical application is hindered by complicated synthesis procedures and high cost. Herein, a highly stable, self-supporting and flexible electrode material for LIBs was constructed by encapsulating spherical FeNi nanoparticles into one-dimensional N-doped carbon fiber film (FeNi/N- CFM) using the electrospinning technique and subsequent heat treatment. The FeNi/N-CFM can be directly used as anode materials for LIBs without conductive additive, current collector and binder. The synergistic effect of uniformly dispersed small FeNi nanoparticles and three-dimensional (3D) conductive network constructed by CF framework effectively improves the utilization rate of active materials, enhances the transport of both electrons and lithium ions, facilitates the electrolyte penetration, and promotes the lithium-ion storage kinetics and stability, thus leading to a greatly enhanced electrochemical performance. Benefiting from the unique architectural feature and flexibility, the FeNi/N-CFM composites employed as binder-free electrodes for LIBs exhibit good lithium storage performance (an initial discharge capacity of 1031.5 mA h g−1 and a reversible capacity of 481.3 mA h g−1 at 100 mA g−1 after 100 cycles), rate capacity (305.1 mA h g−1 at 1000 mA g−1) and outstanding reversibility (coulombic efficiency of around 100 % after 100 cycles). Furthermore, this work also provides a facile and effective pathway to design and fabricate free-standing electrodes.

Transient Phase-Mediated Li+ Transportation in the Lithium Lanthanum Titanate Solid-State Electrolyte.

The lithium lanthanum titanium oxide (LLTO) perovskite is one type of superior lithium (Li)-ion conductor that is of great interest as a solid-state electrolyte for all-solid-state lithium batteries. Structural defects and impurity phases formed during the synthesis of LLTO largely affect its Li-ion conductivity, yet the underlying Li+ diffusion mechanism at the atomic scale is still under scrutiny. Herein, we use aberration-corrected transmission electron microscopy to perform a thorough structural characterization of the LLTO ceramic pellet. We reveal a prevalent transient phase transition of (La, Ti)2O3 existing at the antiphase boundaries between single-crystalline LLTO domains. This transient phase exhibits a specific crystal orientation with the LLTO phase and shows a gradual structural transition to a tetragonal LLTO structure, which enables detailed crystallographic analysis to correlate their formation to the sintering process of LLTO powders into ceramic pellets. We also find that Li diffusion is retarded by this phase and correlated with the excess amount of La, which is corroborated by the theoretical evaluation of the atomistic mechanisms of Li diffusion across this phase.

Reasonable Design and Deep Insight of Efficient Integrated Photorechargeable Li-Ion Batteries by Using a Cu/CuO/Cu2S Electrode.

Herein, Cu-foam-supported CuO nanowire arrays covered with Cu2S nanosheet substrates (Cu/CuO/Cu2S) are adopted as efficient photoelectrodes for photorechargeable lithium-ion batteries (PR-LIBs). The assembled PR-LIB exhibits remarkable solar energy conversion efficiency alongside superior lithium storage capabilities. Without an electrical power supply, the photocharged PR-LIB sustained a discharge process for 63.0 h under a constant current density of 0.05 mA cm-2. The corresponding solar-to-electrical energy conversion efficiency is 4.50%, which is an impressive achievement among recently reported contemporary technologies. Mechanism investigation shows that the Cu/CuO/Cu2S photogenerated carriers augment the extraction and insertion of Li+ according to different oxidation and reduction reactions in the charging and discharging reactions. This research delineates a refined model system and proposes innovative directions for developing efficient heterojunction photoelectrodes, significantly propelling the development of PR-LIB technology.

Robust Nitrogen/Sulfur Co‐Doped Carbon Frameworks as Multifunctional Coating Layer on Si Anodes Toward Superior Lithium Storage

AbstractSilicon (Si)‐based anodes hold great potential for next‐generation lithium‐ion batteries (LIBs) due to their exceptional theoretical capacity. However, their practical application is hindered by the notably substantial volume expansion and unstable electrode/electrolyte interfaces during cycling, leading to rapid capacity degradation. To address these challenges, we have engineered a porous nitrogen/sulfur co‐doped carbon layer (CBPOD) to uniformly encapsulate Si, providing a multifunctional protective coating. This innovative design effectively passivates the electrode/electrolyte interface and mitigates the volumetric expansion of Si. The N/S co‐doping framework significantly enhances electronic and ionic conductivity. Furthermore, the carbonization process augments the elastic modulus of CBPOD and reconstructs the Si‐CBPOD interface, facilitating the formation of robust chemical bonds. These features collectively contribute to the high performance of the Si‐CBPOD anodes, which demonstrate a high reversible capacity of 1110.8 mAh g−1 after 1000 cycles at 4 A g−1 and an energy density of 574 Wh kg−1 with a capacity retention of over 75.6% after 300 cycles at 0.2 C. This study underscores the substantial potential of the CBPOD protective layer in enhancing the performance of Si anodes, providing a pathway for the development of composite materials with superior volumetric energy density and prolonged cyclic stability, thereby advancing high‐performance LIBs.

In-situ assembly of 3D VS2/Reduced graphene oxide with superior lithium ion storage performance: The role of heterojunction

VS2 is a potential anode material for lithium-ion batteries (LIBs) due to its advantageous properties. Herein, a novel three-dimensional (3D) VS2/reduced graphene oxide (rGO) heterostructure (VS2-rGO) was fabricated by in-situ assembly of caterpillar-like VS2 nanosheets on rGO. This 3D VS2-rGO with a well-defined heterojunction interface is engineered to mitigate the volumetric expansion of VS2 during Li + intercalation/deintercalation cycles. This optimized design promotes enhanced conductivity across the heterojunction, facilitating efficient electron and ion transport. The VS2-rGO electrode shows higher reversible capacity and better rate performance (644.02 mA h g−1 at 0.1 A g−1 after 140 cycles, 526.66 mA h g−1 at 2 A g−1) as compared to the pure VS2 electrode (433.69 mA h g−1 at 0.1 A g−1 after 140 cycles, 63.91 mA h g−1 at 2 A g−1). Ex-situ XRD analysis suggests that the Li + storage mechanism in the VS2-rGO electrode involves the initial intercalation, followed by intercalation and conversion. The lower Li + diffusion barrier within the VS2-rGO heterojunction (0.183 eV) compared to the VS2 layers (0.225 eV), as predicted by first-principles calculations, resulting the enhanced Li + transport kinetics and improved cycling performance of the VS2-rGO electrode material. This work offers novel perspectives for the influence of heterojunctions on LIBs.

Construction of flexible asymmetric composite polymer electrolytes for high-voltage lithium metal batteries with superior performance

The primary obstacle hindering the application of composite solid electrolytes lies in the varying demands posed by the Li metal anode and the cathode, which needs to be capable of suppressing dendrite growth and resisting high voltage simultaneously. In this work, a new asymmetric composite solid-state electrolyte prepared via electrospinning and in-situ polymerization is proposed to address these shortcomings. In this bilayer architecture, polyacrylonitrile (PAN) layer of high-voltage tolerance, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) layer of robust mechanical strength and good compatibility towards Li-anode are constructed, and metal-organic-frameworks (MOFs) are pre-embedded within both layers. The unique design provides a wide electrochemical stability window meanwhile ensures uniform lithium deposition. Remarkably, it exhibits a superior lithium utilization of 41 mAh cm−2 using a lean polymer electrolyte precursor and a high critical current density of 2.2 mA cm−2 with a thickness of 40 μm. Beneficial from the formation of a self-adjustable gradient solid electrolyte interphase in the Li/PVDF-HFP interface, the asymmetric electrolyte endows Li||Li and Li||NCM811 cells with excellent cycling stability. Moreover, the solid-state pouch cell exhibits reliable operation under extreme conditions. This work provides inspiration for the design and fabrication of composite solid electrolytes for next-generation high-voltage Li metal batteries.

A general approach to construct alien metal atoms (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn) doped in tin-phthalic acid complex for superior lithium storage

A general approach to construct alien metal atoms (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn) doped in tin-phthalic acid complex for superior lithium storage

Sulfur and Wavy-Stacking Boosted Superior Lithium Storage in 2D Covalent Organic Frameworks.

2D conjugated covalent organic frameworks (c-COFs) provide an attractive foundation as organic electrodes in energy storage devices, but their storage capability is long hindered by limited ion accessibility within densely π-π stacked interlayers. Herein, two kinds of 2D c-COFs based on dioxin and dithiine linkages are reported, which exhibit distinct in-plane configurations-fully planar and undulated layers. X-ray diffraction analysis reveals wavy square-planar networks in dithiine-bridged COF (COF-S), attributed to curved C─S─C bonds in the dithiine linkage, whereas dioxin-bridged COF (COF-O) features densely packed fully planar layers. Theoretical and experimental results elucidate that the undulated stacking within COF-S possesses an expanded layer distance of 3.8 Å and facilitates effective and rapid Li+ storage, yielding a superior specific capacity of 1305 mAh g-1 at 0.5 A g-1, surpassing that of COF-O (1180 mAh g-1 at 0.5 A g-1). COF-S also demonstrates an admirable cycle life with 80.4% capacity retention after 5000 cycles. As determined, self-expanded wavy-stacking geometry, S-enriched dithiine in COF-S enhances the accessibility and redox activity of Li storage, allowing each phthalocyanine core to store 12 Li+ compared to 8 Li+ in COF-O. These findings underscore the elements and stacking modes of 2D c-COFs, enabling tunable layer distance and modulation of accessible ions.

Facile and efficient fabrication of Cu1.04Mn0.96O2 nanosheet anodes with superior electrochemical lithium storage capability

In this work, Cu1.04Mn0.96O2 nanosheets were synthesized via a simple hydrothermal method, and their electrochemical lithium storage properties and reaction mechanisms were investigated. The nanosheet structure effectively promotes electron transfer and shortens the transport path. Additionally, the partial substitution of Cu for Mn decreases the Jahn-Teller distortion of the MnO6 octahedron. Employing as an anode for Li-ion batteries, the specific capacity reached 610.91 mAh g−1 after 100 cycles at a current density of 100 mA g−1.

Li-Sn Alloyed Layer Containing Artificial SEI on Li-Metal Anode for Superior Lithium Metal Batteries: Development and Understanding of Anode/Electrolyte Interfacial Phenomena

Modern civilization and cutting-edge technologies and tools are highly dependent on energy storage devices and demand efficient and long-lasting high-energy-density storage devices. Lithium metal batteries have surpassed their competitors concerning energy density due to their inherent high specific capacity (3860 mAh/g) and the lowest electrochemical potential (-3.04 V vs. standard hydrogen electrode), proving to be one of the most favorable energy storage devices for smart and mobile gadgets, electric automobiles, grid storage, etc. However, safety-threatening and performance-decay challenges associated with lithium metal anodes, such as lithium dendrite formation, uncontrolled parasitic reactions between Li-metal and electrolyte, low coulombic efficiency, dead Li-formation, etc., restrict its employment in practical batteries. The root cause of the dendrite formation is poor Li-ion conductivity of bulk lithium metal, which results in an uneven electric field distribution, leading to non-uniform Li deposition/stripping upon repeated charge/discharge. Herein, a facile chemical reduction process is being opted to fabricate a highly Li-ion diffusive Li-Sn-based artificial SEI layer on the lithium metal surface to prevail over the above-mentioned issues. Therefore, upon careful concentration investigation of reactants, 25 mM precursor concentration (SnCl4 in EC: DMC in 1:1 volume ration) demonstrated the best electrochemical performance, revealing a cumulative capacity of over 700 mAh/cm2 at a current density of 1 mA/cm2 for 1 h in a symmetric cell. Physical characterizations (XRD and SEM-EDS) showed a thin layer containing Li-Sn alloys along with LiCl formed at the lithium metal surface. Possessing high Li-ion diffusivity, Li-Sn alloyed hybrid anode illustrated a gradual decrease in the charge transfer resistance on increasing the concentration, thus, lower overpotential in symmetric cells, in contrast to pristine Li-metal. However, an increase in the electrical resistance has been observed on increasing the precursor concentration due to the presence of the insulating LiCl phase in the protective layer. Moreover, in-situ optical microscopy demonstrated more uniform and on-surface Li-deposition for the hybrid electrode, whereas mossy and dendritic growth on bare Li-metal. Full cells prepared with Li-Sn alloyed anode against NMC532 cathode illustrated stable cycling up to 150 cycles; contrastingly, the cell with pristine Li-metal showed a drastic capacity fade just after 100 cycles, demonstrating the inclination towards safer lithium metal batteries.

Optimizing Hard Carbon Anodes from Agricultural Biomass for Superior Lithium and Sodium Ion Battery Performance.

Biomass-derived carbon materials are gaining attention for their environmental and economic advantages in waste resource recovery, particularly for their potential as high-energy materials for alkali metal ion storage. However, ensuring the reliability of secondary battery anodes remains a significant hurdle. Here, we report Areca Catechu sheath-inner part derived carbon (referred to as ASIC) as a high-performance anode for both rechargeable Li-ion (LIBs) and Na-ion batteries (SIBs). We explore the microstructure and electrochemical performance of ASIC materials synthesized at various pyrolysis temperatures ranging from 700 to 1400 °C. ASIC-9, pyrolyzed at 900 °C, exhibits multilayer stacked sheets with the highest specific surface area, and the least lateral size and stacking height. ASIC-14, pyrolyzed at 1400 °C, demonstrates the most ordered carbon structure with the least defect concentration and the highest stacking height and an increased lateral size. ASIC-9 achieves the highest capacities (676 mAh/g at 0.134 C) and rate performance (94 mAh/g at 13.4 C) for hosting Li+ ions, while ASIC-14 exhibits superior electrochemical performance for hosting Na+ ions, maintaining a high specific capacity after 300 cycles with over 99.5 % Coulombic efficiency. This comprehensive understanding of structure-property relationships paves the way for the practical utilization of biomass-derived carbon in various battery applications.

Facile synthesis of N-doped porous CoO@C nanocubes as anode with superior lithium storage

N-doped porous CoO@C nanocubes were fabricated using a hydrothermal method and annealing process. The uniform wrapped carbon layer effectively mitigates the volume changes during electrochemical reactions. Moreover, the porous carbon layer enhances the electrical conductivity and promotes Li ion diffusion. Therefore, the as-prepared CoO@C nanocubes maintian a capacity of 565 mA h/g at 0.2 A/g after 100 cycles. This stabilization ability is attributed to the introduction of carbon layer and its porous structure, which buffers the volume expansion of cobalt oxide, and increases the surface area and active sites.

Boosting Conversion of the Si-O Bond by Introducing Fe2+ in Carbon-Coated SiOx for Superior Lithium Storage.

SiOx-based anodes are of great promise for lithium-ion batteries due to their low working potential and high specific capacity. However, several issues involving large volume expansion during the lithiation process, low intrinsic conductivity, and unsatisfactory initial Coulombic efficiency (ICE) hinder their practical application. Here, an Fe-SiOx@C composite with significantly improved lithium-storage performance was successfully synthesized by combining Fe2+ modification with a carbon coating strategy. The results of both experiments and density functional theory calculations confirm that the Fe2+ modification not only effectively achieves uniform carbon coating but also weakens the bonding energy of the Si-O bond and boosts reversible lithiation/delithiation reactions, resulting in great improvement in the electrical conductivity, ICE, and reversible specific capacity of the as-obtained Fe-SiOx@C. Together with the coated carbon, the in situ-generated conductive Fe-based intermediates also ensure the electrical contact of active components, relieve the volume expansion, and maintain the structural integrity of the electrode during cycling. And the Fe-SiOx@C (x ≈ 1.5) electrode can deliver a high-rate capacity of 354 mA h g-1 at 2.0 A g-1 and long-term cycling stability (552.4 mA h g-1 at 0.5 A g-1 even after 500 cycles). The findings here provide a facile modification strategy to improve the electrochemical lithium-storage performance of SiOx-based anodes.

Facile synthesis of porous ZnCo2O4 micro–flower decorated with SWCNTs toward superior lithium storage performance

Binary metal oxides ZnM2O4 (A = Co, Fe, Mn) with spinel structures have been widely studied for their high theoretical specific capacity, relatively low cost, controllable morphology and synergistic effect between metal oxides with different charging and discharging mechanisms. However, the electrochemical properties are seriously affected by the huge volume change during cycles and poor electronic conductivity. In this work, porous ZnCo2O4 micro–flowers self–assembled from nano–sheets are successfully prepared by a simple solvothermal method followed by a heat treatment process without the aid of any soft/hard templates, and the resulting ZnCo2O4 active material is further decorated with SWCNTs. The phase composition, morphology characteristic, specific surface area, pore size distribution, elemental valence state and other information of the as–prepared samples are analyzed by relevant techniques such as XRD, FTIR, FESEM, (HR)TEM, TGA, Raman, N2 adsorption/desorption measurement and XPS. As anode materials in Li–ion batteries, the ZnCo2O4/SWCNTs product exhibits high charge/discharge specific capacity, excellent cycling stability and remarkable rate capability. Excellent electrochemical performance benefits from the special micro–/nano–structure characteristics of the as–synthesized ZnCo2O4/SWCNTs electrode material and good dynamic characteristics during cycling.

A novel polymeric lithicone coating for superior lithium metal anodes

Lithium metal (Li) is commonly regarded as the “holy grail” of rechargeable batteries and can serve as anodes for constituting various high-energy lithium metal batteries (LMBs). However, it suffers from two notorious issues: (1) continuous formation of inhomogeneous solid electrolyte interphase and (2) Li dendritic growth. In this study, we developed a novel polymeric lithicone via a new molecular layer deposition (MLD) process, using lithium tert-butoxide (LTB) and hydroquinone (HQ) as precursors. We revealed that such an MLD process enabled the resultant LiHQ to grow linearly in a highly controllable and cyclic mode at a growth rate of 4 Å cycle−1. Furthermore, its low process deposition temperature of 150 °C made it possible to practice high-quality coatings over Li anodes directly. We demonstrated that, very compellingly, this LiHQ coating could protect Li anodes from corrosion and dendritic growth. As a consequence, this LiHQ coating has enabled Li||Li symmetric cells an extremely long cyclability up to 8000 Li-plating/stripping cycles without failure. More excitingly, we demonstrated that, coupled with LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes, the LiHQ-modified Li anodes could help the resultant Li||NMC811 realize a much better capacity retention and much longer cyclability. Thus, this study represents a strategic route for developing commercializeable LMBs.

Rational design of binder, conductive additive and current collector-free Si/reduced graphene oxide film for superior lithium storage

Rational design of binder, conductive additive and current collector-free Si/reduced graphene oxide film for superior lithium storage

Hydrothermal Synthesis of (NH4)2V7O16/Reduced Graphene Oxide Composite with Enhanced Storage Performance for Aqueous Lithium‐Ion Batteries

Herein, a facile hydrothermal method is utilized to prepare a (NH4)2V7O16/reduced graphene oxide (rGO) composite. In an aqueous electrolyte, the obtained (NH4)2V7O16/rGO exhibits superior lithium storage characteristics compared to pure (NH4)2V7O16 in both the three‐electrode configuration and full cell. This improvement can be ascribed to the synergistic effects of incorporation of defective oxygen and rGO modification. The present study proposes a feasible strategy for enhancing the electrochemical properties of (NH4)2V7O16 and demonstrates the potential of the (NH4)2V7O16/rGO composite for aqueous rechargeable lithium‐ion batteries.

Triblock Polymer/Acetylene Black Dual‐Assisted Preparation of Ge/C Nanocomposites with Superior Lithium Storage Performance

AbstractAnode materials based on IV main group elements like Si, Ge, and Sn show great potential for lithium‐ion batteries (LIBs) due to their high specific capacity and low working potential. However, issues such as volume expansion and lattice pulverization hinder their practical usage. To address these issues for Ge, a novel F127 triblock polymer/acetylene black dual‐assisted strategy is proposed to achieve uniform dispersion of polycrystalline Ge, enabling the preparation of Ge@C nanocomposites via hydrogen reduction. The introduced F127 triblock polymer and acetylene black serves a dual purpose to enhance electrical conductivity and prevent Ge nanoparticles from agglomeration. When tested as anode material for LIBs, the Ge@C nanocomposites exhibit exceptional electrochemical performances, demonstrating a sustained specific discharge capacity of 780 mA h g−1 at 0.2 A g−1 after 100 cycles. Moreover, the capacity remains at 767 mA h g−1 even after 300 cycles at a higher current density of 0.5 A g−1. These enhanced lithium storage performances are attributed to the combined effects of well‐dispersed tiny Ge nanoparticles, uniform carbon coating, and an abundance of defects. These factors effectively mitigate the volume expansion and lattice pulverization of Ge nanoparticles and concurrently enhance their conductivity, leading to improved overall performance in LIBs.