Lithium Storage Performance Research Articles

Enhancing lithium storage performance of Carbon/SiOx composite via coating edge-nitrogen-enriched carbon

Silicon oxide (SiOx) exhibits promising potential as a lithium-ion battery anode. However, its practical application is impeded by low electrical conductivity and significant volumetric expansion. To overcome these limitations, we developed a novel co-precipitation and selectively etching approach that leveraged the nitrogen-retaining effect of ZnNCN to prepare an edge-nitrogen-enriched carbon/SiOx composite (NEC@LC-SiOx). This NEC@LC-SiOx showed enhanced electrical conductivity and reduced volumetric expansion. Our innovative approach effectively prevented excessive decomposition of nitrogen species, resulting in a high nitrogen doping content of 21.67 at.% while maintaining a stable structure and mitigated volume expansion during charging and discharging. Consequently, the prepared NEC@LC-SiOx exhibited excellent performance as an anode material for lithium-ion batteries, demonstrating a high reversible specific capacity of 802 mAh/g and outstanding rate capability. This work presents a novel strategy for designing high-performance SiOx anode materials.

Enhancing the Lithium Storage Performance of Phosphorus–Carbon Composites by Reinforcing P–C Bonding with High-Strength Metal Nanoparticles

Enhancing the Lithium Storage Performance of Phosphorus–Carbon Composites by Reinforcing P–C Bonding with High-Strength Metal Nanoparticles

Structural design and investigation of Ti3C2 MXene as a conductive interlayer for improving the lithium-storage performance of PSi@C anode material

Silicon stands out as an ideal anode material for the next generation of lithium-ion batteries (LIBs) due to its abundant sources, low lithiation/delithiation potential, and high specific capacity. However, its practical application is impeded by significant volume expansion, leading to electrode structure damage. In this study, the Porous silicon(PSi)@C/Ti3C2 MXene composite was developed by dispersing porous micro-silicon@carbon (PSi@C) particles into layered stackable Ti3C2 MXene sheets using ultrasonic and freeze drying. The Ti3C2 MXene interlayer played a crucial role in enhancing the conductive crosslinking network between PSi@C particles, and providing efficient channels for electron transport/ion diffusion. Additionally, the Ti3C2 MXene interlayer served as a buffer to accommodate the substantial volume changes in silicon during electrochemical cycling. Consequently, the PSi@C/Ti3C2 MXene composite electrode demonstrated rapid electron/ion conduction and maintained structural stability. Remarkably, the electrode exhibited outstanding long cycle stability with 952 mAh g-1 at 0.5 A g-1 after 200 cycles and excellent rate performance with 542 mAh g-1 at 2 A g-1.

Quantitative pre-intercalation of alkali metal ions enables precisely modulating Li+ storage of MXenes

Ion intercalation is crucial for improving energy storage performance, but controlling the content of intercalated ions is challenging for two-dimensional (2D) electrode materials although it enables clarifying individual intercalation behaviors and thereof pinpointing the intercalation mechanism. Herein, the equal‐content alkali metal ions were successfully manipulated to intercalate into Mo2CTx MXene electrodes via an electrochemistry‐driven approach via the anti‐battery principle. Based on a variety of alkali metal ions pre‐intercalation into the Mo2CTx MXene (M+‐Mo2CTx) electrodes, the lithium storage performance was largely improved. Li+‐Mo2CTx electrode exhibits an outstanding capacity of 395.49 mAh g−1 at 200 mA g−1 after 100 cycles due to the enhanced redox activity induced by high-valence Mo and low -F interlayer exposed surface. Besides, the K+‐Mo2CTx electrode delivers excellent rate performance due to faster ion transfer kinetics originating from the pillaring effect of pre-intercalated K+ ions. In a broader sense, our study opens up a new route to accurately improve the electrochemical performance via precisely tuning the content of ions intercalated into 2D intercalation‐type materials.

Direct regeneration of LiFePO4 cathode by inherent impurities in spent lithium-ion batteries

The direct regeneration method, recognized for its cost-effectiveness, has garnered considerable attentions in the field of battery recycling. In this study, a novel direct regeneration strategy is proposed to repair spent LiFePO4 (S-LFP) cathodes without the need for impurity removal. Instead, the residual conductive carbon and polyvinylidene fluoride (PVDF) in S-LFP are employed as inherent reductive agents. Systematic characterization and analysis reveal that the failure of S-LFP primarily originates from a substantial loss of Li+ and the conversion of LiFePO4 to FePO4. Meanwhile, it is demonstrated that both residual conductive carbon and PVDF play positive roles in promoting the regeneration of S-LFP through distinct mechanisms. As a result, the regenerated LFP exhibits significant recovery in crystal structure and chemical composition as compared to S-LFP, which leads to notably improved lithium storage performance. Furthermore, to further enhance the lithium storage property, a specific amount of glucose (10 %) is introduced during the regeneration of S-LFP, yielding a regenerated product that performs comparably to commercial LFP. Clearly, our approach, in contrast to traditional regeneration methods, maximizes the utilization of residual impurities within S-LFP, resulting in effective regeneration of S-LFP, thereby proving both informative and cost-effective.

Element Screening Engineering for High-Entropy Alloy Anodes: Achieving Fast and Robust Li-Storage With Optimal Working Potential.

While the high-entropy strategy is highly effective in enhancing the performance of materials across various fields, an optimal methodology for selecting component elements for performance optimization is still lacking. Here the findings on uncovering the element selection rules for rational design of high-entropy alloy anodes with exceptional lithium storage performance are reported. It is investigated high-entropy element screening rules by modifying stable diamond-structured Ge with P to induce a tetrahedrally coordinated sphalerite structure for enhanced metallic conductivity, further stabilized by incorporating Zn and other elements. Moreover, both theoretical and experimental results confirm that Li-storage performance improves with increasing atomic number: BZnGeP3 < AlZnGeP3 < GaZnGeP3 < InZnGeP3. InZnGeP3-based electrodes demonstrate the highest Li-ion affinity, fastest electronic and Li-ion transport, largest Li-storage capacity and reversibility, and best mechanical integrity. Further element screening based on the above criteria leads to high entropy alloy anodes with metallic conductivity like GaCuSnInZnGeP6, GaCu(or Sn)InZnGeP5, CuSnInZnGeP5, InZnGePSeS(or Te), InZnGeP2S(or Se) which show superior Li-storage performances. The excellent phase stability is attributed to their high configurational entropy. This study offers profound insights into element screening for high-entropy alloy-based anodes in Li-ion batteries, providing guidance and reference for the element combination and screening of other high-entropy functional materials.

Vertically Aligned MoS2 Nanosheets with Increased Interlayer Spacing on Hollow Polypyrrole Nanotubes for Enhanced Lithium and Sodium Storage Performance

Vertically Aligned MoS₂ Nanosheets with Increased Interlayer Spacing on Hollow Polypyrrole Nanotubes for Enhanced Lithium and Sodium Storage Performance

Nitrogen doping enhances pseudocapacitive lithium storage and ionic conductivity in Ti2Nb2O9 nanosheets

Titanium-niobium oxides (TixNbyO2x+2.5y) are promising anode materials for lithium-ion batteries due to their suitable lithium insertion potential, excellent rate performance, cycling stability, and considerable capacity based on multi-electron reactions. However, the intrinsic low electrical conductivity and rapid capacity decay during cycling limit their application. In this study, nitrogen-doped Ti2Nb2O9 nanosheets were synthesized using a chemical exfoliation method and the subsequent high-temperature phase transition. Meanwhile, introducing nitrogen atoms reduced the bandgap and increased the material's electrical conductivity. Thus, the lithium storage performance of the N-TNO electrode was improved with a reversible capacity of 348.1 mAh g−1.

Incorporation of SnSe2/SnO2 heterostructures in carbon nanotubes for excellent lithium storage performance

As a new type of negative electrode material, tin-based material exhibits a high theoretical capacity. However, tin-based anode materials always undergo severe volume change upon alloying reaction during lithium insertion and extraction, which leads to the pulverization of the active materials and poor electrochemical performance, seriously hampering its practical application. In this work, oxygen-containing group functionalized carbon nanotubes (FCNTs) were facilely obtained, and the three-dimensional crosslinked SnSe2-SnO2@FCNTs multiphase materials were prepared by solvothermal and high-temperature heat treatment. The formation of Sn-O-C bonds from oxygen-containing functional groups of FCNTs combined with Sn can promote the electric connection and integrity of the composites. The implanted defects in FCNTs can not only be beneficial to anchoring SnO2 and SnSe2 nanoparticles, but also helpful to the penetration of Li+ ions into the electrodes from electrolyte. In addition, the large Fermi energy difference between SnSe2 and SnO2 nanoparticles results in the formation of a built-in electric field at the interface of the multiphase materials, accelerating the diffusion of ions. The smaller size of the multiphase materials leads to significant pseudocapacitive behavior, which facilitates the highly reversible surface/interface adsorption. Under the multiple effects of FCNTs, SnSe2, and SnO2, the SnSe2-SnO2@FCNTs multiphase materials exhibited excellent electrochemical performance. At a current density of 0.1A·g-1, a discharge specific capacity of 898.0mAh·g-1 was achieved. When the current density was increased to 2A·g-1, it still exhibited a discharge specific capacity of 443.9mAh·g-1. After a long charge/discharge cycling at 1A·g-1 over 450 cycles, it still showed a specific capacity of ~ 400mAh·g-1. This work significantly demonstrated the enhanced Li-storage performance of SnSe2-SnO2 heterostructures incorporated in the functionalized multi-walled CNTs. This opens a new way to synthesize advanced tin-based materials as high-performance anodes for high-energy density lithium-ion batteries.

Facile one-pot synthesis of Bi2S3 nanorod @ N, S co-doped carbon composite for high performance lithium ion batteries

Bismuth sulfide is favoured in lithium ion batteries due to its high specific capacity of 625 mAh/g. However, the Bi2S3 anode faces severe volume expansion problems during the lithium intercalation process, resulting in continuous electrode fragmentation and rapid degradation of lithium storage performance. In this study, Bi2S3 nanorod@N, S co-doped carbon composite prepared by a simple sintering method was used as the anode material for lithium ion batteries. 1D Bi2S3 nanorods with a length of 1 μm and a diameter of 50 nm were loaded in situ on 2D N, S co-doped carbon nanosheets. This unique structure can not only alleviate the volume change of bismuth sulfide, but also effectively shorten the diffusion distance of lithium ions, thereby improving the cycling stability and rate capability at the same time. The discharge capacity of Bi2S3@N, SC remained at 583.4 mAh g –1 after 400 cycles at 0.5 A g–1. Even at a high current density of 2 A/g, the discharge capacity of Bi2S3@N, SC still reached 374.3 mAh g –1. This simple method also can be extended to the preparation of other metal sulfide composites.

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.

Three-dimensional porous structure CoP/N-doped carbon nanospheres as anode for enhanced lithium storage performance

Transition metal phosphides (TMPs) with high theoretical capacities and safe operating voltage are recognized as prospective anode materials for lithium-ion batteries (LIBs). While, the huge volume expansion and low conductivity of TMPs still restrict their applications. Engineering nanostructured composites consisting of TMPs and conductive carbon-based materials is of great importance to improve electrochemical performance. Herein, a novel and facile pyrolysis-oxidation-phosphidation approach is designed to fabricate porous nanospheres composing of CoP nanoparticles and N-doped carbon substrate. The abundant pores in CoP/N-C provide ample active sites for lithium storage and facilitate Li+ transport. The introduction of N-doped carbon substrate enhances the electrical conductivity, allowing CoP to maintain its structure during cycling. The CoP/N-C anode achieves remarkable cycle performance, maintaining an extremely stable cycle life over 2000 cycles at 5 A g−1. More importantly, the full cell consisting of CoP/N-C and LiFePO4 also exhibits a prominent cycling durability with a capacity retention of 96.5 % at 0.1 A g−1 after 150 cycles. This work proposes a simple and feasible structural engineering strategy, which can provide a new way for optimizing the electrochemical performance of conversion-type anode materials.

Electrochemical Kinetics of LiFePO4 Cathode Material in Non-flammable Inorganic Liquid Electrolyte.

We unveil the fundamental insights of electrochemical kinetics of LFP cathode material and the passivation layer formation in the SO2-based non-flammable inorganic liquid electrolyte (IE). The influence of temperature and electrochemical potential cutoff in the electrochemical activity of LFP cathode and IE is disclosed. Furthermore, the materials compatibility, structural and chemical stability of LFP in IE is demonstrated using very slow galvanostatic cycling in combination with LiFePO4||Li0.1FePO4 symmetric cells. The lithium storage performance of LFP half-cell using inorganic electrolyte is presented with the optimum voltage window. LFP half-cells exhibit discharge capacities of 147, 111, and 75 mAh/g at 1, 4, 8 C rates, respectively, with coulombic efficiencies of ~99.98 %. The electrochemical behavior and mechanism of LFP||Graphite cell in IE is investigated while concurrently tracking the electrochemical potentials of LFP and Graphite half-cell.

Unveiling the Influences of In Situ Carbon Content on the Structure and Electrochemical Properties of MoS2/C Composites.

In this work, a MoS2/C heterostructure was designed and prepared through an in situ composite method. The introduction of carbon during the synthesis process altered the morphology and size of MoS2, resulting in a reduction in the size of the flower-like structures. Further, by varying the carbon content, a series of characterization methods were employed to study the structure and electrochemical lithium storage performance of the composites, revealing the effect of carbon content on the morphology, structure characteristics, and electrochemical performance of MoS2/C composites. The experimental setup included three sample groups: MCS, MCM, and MCL, with glucose additions of 0.24 g, 0.48 g, and 0.96 g, respectively. With increasing carbon content, the size of MoS2 initially decreases, then increases. Among these, the MCM sample exhibits the optimal structure, characterized by smaller MoS2 dimensions with less variation. The electrochemical results showed that MCM exhibited excellent electrochemical lithium storage performance, with reversible specific capacities of 956.8, 767.4, 646.1, and 561.4 mAh/g after 10 cycles at 100, 200, 500, and 1000 mA/g, respectively.

Nitrogen plasma-induced phase engineering and titanium carbide/carbon nanotubes dual conductive skeletons endow molybdenum disulfide with significantly improved lithium storage performance

MoS2/Ti3C2 MXene composite has emerged as a promising anode material for lithium storage due to the synergistic combination of high specific capacity offered by MoS2 and conductive skeleton provided by Ti3C2 MXene. However, its two-dimensional/two-dimensional (2D/2D) structure is susceptible to collapse after long cycles, while the inherent low conductivity of MoS2 limits its rate performance. In this study, we developed a novel approach combining plasma-induced phase engineering with dual skeleton structure design to fabricate a unique P-MoS2/Ti3C2/CNTs anode material featuring highly conductive 1T phase MoS2 and a stable one-dimensional/two-dimensional (1D/2D) architecture. Within this architecture, growth of MoS2 nanosheets on the surface of Ti3C2 cross-linked by carbon nanotubes (CNTs) was achieved. The resulting Ti3C2/CNTs dual skeleton not only provides robust mechanical support to prevent structural collapse during long cycles but also offers increased specific surface area and additional Li+ storage space, thereby enhancing the lithium storage capacity of the composite. Subsequent N2 plasma treatment induced a phase transition in MoS2 from 2H to 1T configuration. Density functional theory (DFT) calculations confirmed that the induced 1T-MoS2 exhibits higher conductivity and lower Li+ diffusion barrier compared to 2H-MoS2. Benefiting from these synergistic effects, our P-MoS2/Ti3C2/CNTs anode demonstrated remarkable electrochemical performance including a high reversible specific capacity of 1120 mAh g−1 at 0.1 A g−1, excellent cycling stability with a specific capacity retention of 670 mAh g−1 after 600 cycles at 1 A/g, and superior rate performance with a specific capacity of 614 mAh g−1 at 2 A g−1. This combined modification strategy will serve as guidance for designing other energy storage materials.

Stress-relieved hollow porous carbon nanoring structures anchored with ZnCo2O4 nanoparticles towards super stable lithium storage

Stress-induced structural mechanical instability is a common occurrence in the electrode material during electrochemical cycling, especially for composite material systems. The structural mechanics engineering of nanocomposites comprising electrochemical active materials and carbon with novel structures holds great promise in addressing this issue. However, conventional carbonaceous materials often encounter challenges in long-term durability and high specific capacity stemming from their intrinsic uneven stress distribution and few active sites. Herein, finite element analysis reveals that the ring-like structure effectively mitigates stress concentration from expansion and possesses high packing density, outperforming traditional nanosphere and nanocube architectures. Accordingly, nanocomposites consisting of hollow porous nanostructured N-doped carbon nanorings (N-CNRs) anchored with bimetallic ZnCo2O4 nanoparticles are designed, which exhibit an extraordinary cycling performance for lithium storage with 96.4 % capacity retention following 1000 cycles and an impressively low storage degradation rate of 0.00357 % per cycle, as well as displaying an excellent specific capacity (1218 mA h/g at 0.1 A g−1) and outstanding rate performance (565 mA h/g at 5.0 A g−1). The well-engineered design nanocomposite features the synergistic effect of electrochemically active ZnCo2O4 nanoparticles integrated with structurally stable carbon nanorings for enhanced electrochemical performance.

Synthesis of porous Mg2MnO4 spinel microspheres and enhanced lithium storage properties

Porous Mg2MnO4 spinel microspheres were synthesized by a facile solvothermal method. Various techniques such as X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, were used to characterize the phase composition, morphology and electronic structure of materials. The results show that Mg2MnO4 spinel material was obtained at the temperature of 600–800 °C and has a microsphere structure. The microspheres were assembled by nanoparticles, and the particle size increases with the increase of annealing temperature. Analyses of XPS spectra reveal that Mn exists in multiple valence states (+2, +3, +4) in Mg2MnO4 materials, and all the materials are mixed spinel with Mg2+ and Mn2+/3+/4+ ions occupy both tetrahedral and octahedral sites of spinel structure, and the degree of inversion decreases with increasing annealing temperature. Mg2MnO4 microspheres exhibit excellent lithium storage performance, the first discharge specific capacity of M2MO-8 is 835.3 mAh g−1 under a voltage window of 0–3 V and with a current density of 100 mA g−1, and after 100 cycles the discharge capacity of the material is as high as 406.5 mAh g−1. In addition, this material shows high cyclic reversibility. The enhanced lithium storage properties of the material can be attributed to its porous structure, which promote the transport of lithium ions and reduce the damage to the structure caused by the volume change during the charge and discharge process.

Constructing stress-release layer on Si nanoparticles for high-performance lithium storage

Tailing structures of silicon anode to alleviate the mechanical stress has an important significance in the development of lithium-ion batteries (LIBs). Herein, the stress-released layer of N-doped cubic carbon on the surface of Si nanoparticles (Si@NCC) is explored to stabilize the electrode. Endowed with the unique superiority, the Si@NCC electrode delivers an impressive lithium storage performance with high specific capacity of 630 mAh/g at 0.1 A/g, excellent cycling stability (72.0 % capacity retention after 100 cycles at 0.1 A/g) and good rate capability (375 mAh/g at 2 A/g). It has been demonstrated that the N-doped cubic carbon shell with high conductivity can effectively limit the expansion and agglomeration of Si nanoparticles. Besides, the COMSOL simulations of the stress distributions in materials confirm that the N-doped cubic carbon layer could remarkably decrease the stress originated from the volume expansion of Si nanoparticles during the lithiation. Therefore, this work provides ideas for the mechanical effect of Si-based anodes for lithium storage and sheds lights on the designing advanced materials toward high-performance energy storage devices.

Solid-State Construction of CuO-Cu2O@C with Synergistic Effects of Pseudocapacity and Carbon Coating for Enhanced Electrochemical Lithium Storage.

The pseudocapacitive effect can improve the electrochemical lithium storage capacity at high-rate current density. However, the cycle stability is still unsatisfactory. To overcome this issue, a multivalent oxide with a carbon coating represents a plausible technique. In this work, a CuO-Cu2O@C composite has been constructed by a one-step bilayer salt-baking process and utilized as anode material for lithium-ion batteries. At a current density of 2.0 A g-1, the as-prepared composite delivered a stable discharge capacity of 431.8 mA h g-1 even after 600 cycles. The synergistic effects of the multivalence, the pseudocapacitive contribution from copper, and the carbon coating contribute to the enhanced electrochemical lithium storage performance. Specifically, the existence of cuprous suboxide improves the electrochemical conductivity, the pseudocapacitive effect enhances the lithium storage capacity, and the presence of carbon ensures cycle stability. The testing results show that CuO-Cu2O@C composite has broad application prospects in portable energy storage devices. The present work provides an instructive precedent for the preparation of transition metal oxides with controllable electronic states and excellent electrochemical performance.

Hollow core-shell Si-PEI@ZIF-67 with cross-linking effect for high-performance Li-ion batteries

Owing to its extremely high theoretical capacity (4200 mAh g−1), silicon (Si) has emerged as a promising candidate for lithium-ion batteries (LIBs) anodes. However, challenges such as a volumetric expansion of up to 300 % and poor electrical conductivity have impeded its application. Here, hollow core-shell Si-PEI@ZIF-67 synthesized via a simple one-pot method utilizing the unique properties of ZIF-67, including its porous nature, high surface area, and well-ordered structure, ZIF-67 coating effectively mitigates the volume expansion of nano-Si during cycles. Hollow core-shell structure can accelerate ion transfer and alleviate volume expansion. Moreover, Co2+ enrichment in the coating promotes the formation of a strong cross-linking network with the binder sodium alginate. This interaction not only enhances the adhesion between active material and current collector but also accelerates ion transport. Si-PEI@ZIF-67 composites demonstrate outstanding lithium storage performance in LIBs, achieving a stable capacity of 1134.4 mAh g−1 after 500 cycles at 1000 mA g−1. In addition, the discharge capacity of 828.7 mAh g−1 is maintained after 200 cycles at the high current density of 5000 mA g−1. The innovative synthesis method, utilizing ZIF-67 as a coating for nano-Si and establishing an interconnected network with the binder, offers a novel approach for other anodes.