High-performance Lithium-ion Storage Research Articles

Carbon coated and oxygen vacancies incorporated Wadsley-Roth phase molybdenum niobium oxide for high-performance lithium-ion storage

Nb-based oxides with Wadsley-Roth shear structure have been aroused extensive research interest as promising anode for Li-ion batteries, due to the multi-electron redox, safe working voltage and open structural framework. However, the low intrinsic electronic conductivity limits their further practical applications. Herein, the lithium storage performances of MoNb6O18 with Wadsley-Roth shear structure are optimized by carbon coating and oxygen vacancies (VO-MNO@C), which synthesized with freeze-drying and subsequently heat treatment. As expected, the VO-MNO@C electrode demonstrates a high initial reversible capacity of 259.6 mAh/g at 0.2C and the capacity retention rate of 85.7 % after 200 cycles at 1C. Moreover, the reversible of Mo6+/Mo5+ and Mo5+/Mo4+ redox reaction can be effectively improved. In situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectroscopy (XPS) characterization indicate that VO-MNO@C undergoes a solid-solution structural evolution disclosing the stepwise reaction of Mo5+/Mo6+, Mo4+/Mo5+, Nb4+/Nb5+ and Nb3+/Nb4+ redox couples with a small volume variation of 5.7 %. Also, the full cell based on commercial LiMn2O4 cathode and VO-MNO@C anode displays an operating voltage about 2.4 V with the high energy density of 681.4 Wh/kg (calculated with the mass of anode). This work will offer more insights for the development of Wadsley-Roth shear structure anode materials with excellent Li-ion storage properties.

Rational design of germanium–copper based nanocomposite anodes for high-performance lithium-ion storage

The rising energy demand in the 21st century has necessitated a shift from fossil fuels to irregular renewable sources for carbon neutrality. Therefore, energy-storage systems are crucial for storing intermittently produced energy. Electric vehicles (EVs), which are expected to replace internal combustion engines, are in high demand for achieving carbon neutrality. The development of efficient secondary batteries (such as lithium-ion batteries; LIBs) is vital for increasing the energy-storage capacity and driving range of EVs. Currently, the most commercialized carbon-based anode material has a capacity of 372 mAh g−1. However, this capacity is insufficient to produce the high-capacity batteries required in the current market. Therefore, in this study, GeO2, which can store 8.4 lithium atoms in one molecule, was selected as the target material. To enhance its electrochemical properties, conductive Cu and C were introduced into GeO2. The composites were synthesized via high-energy ball milling, a simple and easy method to scale up. Three types of GeO2/Cu@C composites, GeO2/Cu@C (10, 20, and 30 wt%), were prepared by varying the carbon content. Among them, GeO2/Cu@C (20 wt%) exhibited an average reversible capacity of 660.6 mAh g−1 after 200 cycles, with a capacity retention of 75.4 % at a current density of 0.1 A g−1. Even at a high current density of 0.5 A g−1, its average capacity and capacity retention were 672.3 mAh g−1 and 99.5 %, respectively, after 100 cycles. Moreover, galvanostatic intermittent titration technique analysis revealed that the Li+ diffusion coefficient of GeO2/Cu@C (20 wt%) was higher than those of the other electrodes. The full-cell with the NCM622 cathode exhibited a high energy density of 284.9 Wh kg−1. Therefore, the GeO2/Cu@C (20 wt%) electrode is anticipated to be a potential anode for long-term LIB cycling.

Ni0.05Ti1.95Nb10O29: an advanced anode material for high-performance lithium-ion storage

Ni0.05Ti1.95Nb10O29: an advanced anode material for high-performance lithium-ion storage

Designing electron/ion dual-phase conductor Ni@TiO2 for high-performance lithium-ion storage: Combining insertion and space charge mechanism

In this study, we construct an yolk-shell Ni@TiO2 nanosphere to investigate its performance in lithium-ion batteries. The composite possesses a synergistic storage mode consisting of a Li+-accepting and an electron-accepting phase. Used as an anode material, it delivers ultra-high specific capacity with excellent rate performance and cycling stability. In situ magnetic characterization and thermodynamic simulation reveal the existence of space charge storage mechanism. We propose an overall view on the Li storage mechanism of the Ni@TiO2 and demonstrate the importance of space charge storage for performance improvement in Li-ion batteries.

In Situ Hybridization Strategy Constructs Heterogeneous Interfaces to Form Electronically Modulated MoS2/FeS2 as the Anode for High-Performance Lithium-Ion Storage.

The interfacial effect is important for anodes of transition metal dichalcogenides (TMDs) to achieve superior lithium-ion storage performance. In this paper, a MoS2/FeS2 heterojunction is synthesized by a simple hydrothermal reaction to construct the interface effect, and the heterostructure introduces an inherent electric field that accelerates the de-embedding process of lithium ions, improves the electron transfer capability, and effectively mitigates volume expansion. XPS analysis confirms evident chemical interaction between MoS2 and FeS2 via an interfacial covalent bond (Mo-S-Fe). This MoS2/FeS2 anode shows a distinct interfacial effect for efficient interatomic electron migration. The electrochemical performance demonstrated that the discharge capacity can reach up to 1217.8 mA h g-1 at 0.1 A g-1 after 200 cycles, with a capacity retention rate of 72.9%. After 2000 cycles, the capacity retention is about 61.6% at 1.0 A g-1, and the discharge capacity can still reach 638.9 mA h g-1. Electrochemical kinetic analysis indicated an enhanced pseudocapacitance contribution and that the MoS2/FeS2 had sufficient adsorption of lithium ions. This paper therefore argues that this interfacial engineering is an effective solution for designing sulfide-based anodes with good electrochemical properties.

Advanced Multilayered Electrode with Planar Building Blocks Structure for High-Performance Lithium-Ion Storage.

To achieve the high-performance of lithium-ion battery, the optimization of electrode materials has generally been considered as the one of the important methods. But most of those works pay attention to the new materials preparation or interface modification rather than the structural innovation. Here, an advanced electrode (GDY/BP/GDY-E) with multilevel layered architecture constructed by planar building blocks stacking structure has been designed and fabricated to explore the structure design of the electrode. This new structure is assembled by graphdiyne (GDY) and black phosphorus (BP) in parallel to form a building block (GDY/BP/GDY). The electric fields between the two GDY sides of the planar building block structure contribute to the superior migration dynamics of lithium ions and desirable pseudocapacitance behavior. Meanwhile, the planar stacking structure of GDY/BP/GDY can efficiently inhibit volume expansion of BP and a series of parasitic reactions of electrolytes during the long-term cycling. The advanced GDY/BP/GDY-E exhibits excellent high-rate performance (1418.8 mAh g-1 at 0.1 A g-1 ) and cycling stability (391.7 mAh g-1 after 5000 cycles at 10 A g-1 ). Such structural design of electrode materials shows a new way to develop high-performance electrodes.

Encapsulating flower-like MoS2 nanosheets into interlayer of nitrogen-doped graphene for high-performance lithium-ion storage

Layered molybdenum disulfide (MoS2) is a promising anode material for lithium-ion storage and its coupling with graphene can further improve the specific capacity and cycling stability. In this work, a feasible polyacrylamide (PAM)-assisted approach to prepare the flower-like MoS2 nanosheets encapsulated by nitrogen-doped graphene (FL-MoS2/N-G) is proposed. The PAM is taken as the directing agent for the layered assembly of graphene and further confined growth of FL-MoS2 in the interlayers of the graphene. The unique encapsulation construction of MoS2 and N-doped graphene leads to the high loading of active species and stabilized structural integrity after the continuous Li+ ion intercalations. Theoretical simulation results reveal that the MoS2 nanosheets coupled with N-doped graphene can accelerate the charge transfer process and create extra lithiation sites with decreased diffusion resistance of Li+ ions. As the anode material in lithium-ion batteries (LIBs), the target FL-MoS2/N-G composite exhibits a high reversible capacity of about 1202 mAh g−1 at 0.2 A g−1 and it can remain 835 mAh g−1 even at 5 A g−1, highlighting an excellent rate capacity. Additionally, the FL-MoS2/N-G anode is also capable of delivering a long-term cycling performance with a capacity retention of about 78% after 800 cycles. Furthermore, benefiting from the fast charge transfer process of the FL-MoS2/N-G dominated by surface capacitive behavior, the lithium-ion hybrid capacitor with good electrochemical performance was fabricated to brighten its practical application prospect. The current work presents a new insight into the fabrication of high-loading MoS2/N-doped graphene composites with unique nanostructures for high-performance lithium-ion storage.

Rational design of hollow Ti2Nb10O29 nanospheres towards High-Performance pseudocapacitive Lithium-Ion storage

Ti2Nb10O29, as one of the most promising anode materials for lithium-ion batteries (LIBs), possesses excellent structural stability during lithiation/delithiation cycling and higher theoretical capacity. However, Ti2Nb10O29 faces some challenges, such as insufficient ion diffusion coefficient and poor electronic conductivity. To overcome these problems, this study investigates the effect of applying nanostructure engineering on Ti2Nb10O29 and the lithium storage behaviors. We successfully synthesized hollow Ti2Nb10O29 nanospheres (h-TNO NSs) via solvothermal method using phenolic resin nanospheres as the template. The effects of using a template or not and the annealing atmospheres on the microstructures of the as-prepared Ti2Nb10O29 are investigated. Different nanostructures (porous Ti2Nb10O29 nanoaggregates (p-TNO NAs) without a template and core-shelled Ti2Nb10O29@C nanospheres (cs-TNO@C NSs)) were formed through annealing in Ar. When examined as anodes for LIBs, the h-TNO NSs electrode with hollow spherical structure displayed a better lithium storage performance. Compared to its counterparts, p-TNO NAs and cs-TNO@C NSs, h-TNO NSs electrode exhibited a higher reversible capacity of 282.5 mAh g−1 at 1C, capacity retention of 79.5% (i.e., 224.6 mAh g−1) after 200 cycles, and a higher rate capacity of 173.1 mAh g−1 at 10C after 600 cycles. The excellent electrochemical performance of h-TNO NSs is attributed to the novel structure. The hollow nanospheres with cavities and thin shells not only exposed more active sites and improved ion diffusion, but also buffered the volume variation upon cycling and facilitated electrolyte penetration. This consequently enhanced the lithium storage performance of the electrode and its high pseudocapacitive contribution (90% at 1.0 mV s−1).

Domain-limited growth strategy to construct Fe3C@C@CNTs heterogeneous interfaces for multi-functional high-performance lithium-ion storage and microwave absorption

Rational designed cost-effective material is significant in the field of electric energy storage and microwave absorber. In this work, carbon coated Fe3C nanoparticles (NPs) encapsulated carbon nanotubes (Fe3C@C@CNTs) is delicately constructed through in-situ chemical vapor deposition (CVD) strategy. As a promising anode material for lithium-ion batteries (LIBs), the Fe3C@C@CNTs nanocomposite facilitates electron transport with intensive interfacial interaction, making it an ideal prototype to thoroughly understand the mechanisms of interatomic charge transfer mechanism. As a result, this well-designed Fe3C@C@CNTs anode exhibits a high reversible capacity of 1027 mAh g−1 after 150 cycles at 0.1 A g−1 and excellent cycling stability with 71 % capacity retention at 519 mAh g−1 after 1000 cycles at 1.0 A g−1. Electrochemical kinetic results confirm that the pseudocapacitance contributions reach up to 90.1 % at 1.0 mV s−1, and the higher pseudocapacitance characteristic is ascribed to the multi-dimensional encapsulated by CNT layer and carbon layer. Meanwhile, depending on the peculiar cavity structure and heterogeneous interfaces effects constructed by multi-dimensional encapsulated structure, the minimum reflection loss (RLmin) of Fe3C@C@CNTs nanocomposite can reach up to −67.63 dB in effective absorption bandwidth (EAB) of 7.12 GHz with the optimal matching thickness of 2.28 mm, suggesting its extensive potential application as practical alternative absorber. This domain-limited growth strategy opens a new horizon to achieve multi-functional application and beyond for Fe-based nanomaterial.

Hollow Porous CoO@Reduced Graphene Oxide Self-Supporting Flexible Membrane for High Performance Lithium-Ion Storage.

We report an environment-friendly preparation method of rGO-based flexible self-supporting membrane electrodes, combining Co-MOF with graphene oxide and quickly preparing a hollow CoO@rGO flexible self-supporting membrane composite with a porous structure. This unique hollow porous structure can shorten the ion transport path and provide more active sites for lithium ions. The high conductivity of reduced graphene oxide further facilitates the rapid charge transfer and provides sufficient buffer space for the hollow Co-MOF nanocubes during the charging process. We evaluated its electrochemical performance in a coin cell, which showed good rate capability and cycling stability. The CoO@rGO flexible electrode maintains a high specific capacity of 1103 mAh g-1 after 600 cycles at 1.0 A g-1. The high capacity of prepared material is attributed to the synergistic effect of the hollow porous structure and the 3D reduced graphene oxide network. This would be considered a promising new strategy for synthesizing hollow porous-structured rGO-based self-supported flexible electrodes.

Carbon-coated MXene nanofiber as a free-standing electrode for high-performance lithium-ion storage

Carbon-coated MXene nanofiber as a free-standing electrode for high-performance lithium-ion storage

Fully sp2-carbon connected polymeric frameworks with rotatable conformation-enhanced lithium-storage performance

Fully sp2-carbon connected polymeric frameworks with conformationally tuned flexibilities, rich redox sites, and porous structures, were constructed, and fabricated with carbon nanotubes to film-like electrodes for high-performance electrochemical lithium-ion storage.

Preparation and High-performance Lithium-ion Storage of Cobalt-free Perovskite High-entropy Oxide Anode Materials

Preparation and High-performance Lithium-ion Storage of Cobalt-free Perovskite High-entropy Oxide Anode Materials

Heterogeneous yolk-shell spindle of amorphous iron polyvanadate@MIL-88A for high-performance lithium-ion storage

Heterogeneous yolk-shell spindle consisting of amorphous iron polyvanadate hollow spindle and residual MIL-88A is constructed through the controlled etching-deposition reaction between NH4VO3 and MIL-88A. As anode material of lithium-ion batteries, iron polyvanadate@MIL-88A can deliver discharge capacity of 959 mAh/g at 1 A/g after 320 cycles and 440 mAh/g at 5 A/g after 400 cycles, superior to pure iron polyvanadate hollow spindle, MIL-88A and FeVO4 composites. High reversible capacity, stable cycling performance and good rate capability of iron polyvanadate@MIL-88A are attributed to the composition effect.

Boosted charge transfer in ReS2/Nb2O5 heterostructure by dual-electric field: Toward superior electrochemical reversibility for lithium-ion storage

Heterostructures with the electric field effect can excite the charge transfer kinetics of materials due to the driving force of the electric field. Herein, we report a new ReS2/Nb2O5 heterostructure of rhenium disulfide coupled to niobium oxide with a mutually compatible band structure and enriched oxygen vacancies. The unique heterostructure can facilitate the redistribution of charges to induce built-in electric fields and microlocalized electric fields. As expected, the ReS2/Nb2O5 heterostructure shows a superior lithium-ion reversible capacity of 805 mAh g−1 after 2400 h at 0.10 A g−1, and 414 mAh g−1 at 2.00 A g−1. In addition, in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy analysis reveal the phase transition process of the ReS2/Nb2O5 heterostructure during the electrochemical reaction. This provides deeper insights into the construction of high-performance lithium-ion storage materials based on heterostructures with dual-electric field-driven charge transfer.

Rational Design of Silicon Nanodots/Carbon Anodes by Partial Oxidization Strategy with High-Performance Lithium-Ion Storage.

Silicon (Si) is considered a promising anode material for rechargeable lithium-ion batteries (LIBs) due to its high theoretical capacity, low working potential, and safety features. However, the practical use of Si-based anodes is hampered by their huge volume expansion during the process of lithiation/delithiation, and they have relatively low intrinsic electronic conductivity, therefore seriously restricting their application in energy storage. Here, we propose a facile approach to directly transform siliceous biomass (bamboo leaves) into a porous carbon skeleton-wrapped Si nanodot architecture through a partial oxidization strategy and magnesium thermal reaction to obtain a high Si nanodot component composite (denoted as Si/C-O). With the synergistic effect of the porous carbon skeleton structure and uniformly dispersed Si nanodots, the Si/C-O composite anode with a stable structure that can avoid pulverization and accommodate volume expansion during cycling is fabricated. As expected, the biomass-converted Si/C-O anode not only presents a high Si component (59.7 wt %) by TGA but also exhibits an excellent capacity of 1013 mAh g-1 at 0.5 A g-1 and robust cycling stability with a capacity retention of 526 mAh g-1 after 650 cycles. Moreover, the Si/C-O anode demonstrates considerable performance in practical LIBs when assembled with a commercial LiNi0.8Co0.1Mn0.1O2 cathode. This work provides an effective strategy and long-term insights into the utilization of porous Si-based materials converted by biomass to design and synthesize high-performance LIB materials.

Ultrathin graphdiyne oxide-intercalated MXene: A new heterostructure with interfacial synergistic effect for high performance lithium-ion storage

Two-dimensional (2D) layered heterostructures demonstrate strong interfacial synergistic effect, promote ion transfer and accelerate electrochemical reaction kinetics, and have great development potential in the field of energy storage. Here, ultra-thin 2D graphdiyne oxide (GDYO) was successfully prepared and creatively used as an intercalator to form a sandwich-like heterostructure with MXene (Ti3C2Tx) through electrostatic self-assembly. Intercalation of GDYO effectively extends the interlayer spacing of Ti3C2Tx nanosheets and meanwhile generates atomic interfacial electric fields within the heterostructure, leading to desirable pseudocapacitive behaviors and superior lithium-ion migration kinetics. Theoretical and experimental data reveal that the electrochemical performance of the heterostructure is superior to that of pure Ti3C2Tx or GDYO nanosheets when utilized as anodes for lithium-ion storage. A reversible capacity of ≈490.0 mAh g−1 at 2.0 A g−1 is attained by the Ti3C2Tx/GDYO-5 wt% heterostructure (≈770.0 mAh g−1 at 0.1 A g−1) with a long cycle life of 489.2 mAh g−1 after 1000 cycles.

Tailoring interfacial interaction in GaN@NG heterojunction via electron/ion bridges for enhanced lithium-ion storage performance

In this paper, gallium nitride (GaN) nanoparticles is synthesized on the nitrogen-doped graphene (NG) (GaN@NG). X-ray absorption fine structure (XAFS) shows the distinct interfacial interaction (Ga–N/NC). This well-designed GaN@NG shows good reversible capacity (793.2 mAh/g at 0.1 A/g) and cycling durability with 98.5 % capacity retention at 2.0 A/g after 2000 cycles. Both DFT analysis and electrochemical kinetic analysis reveal that the configuration of intriguing electron and ion bridges is able to control and tailor the interfacial interaction via the interfacial coupled chemical bonds in GaN@NG heterojunction. Such electron/ion bridges can enhance the interfacial charge transfer kinetics and prevent pulverization/aggregation via the ion/electron channel during the cycling. As expected, the lithium-ion full cell (LiFePO4/C//GaN@NG) exhibits impressive energy and power densities and maintains superior cycling stability. This electron/ion bridges-related structural engineering strategy can open opportunities for the traditional electrode material to achieve the high-performance lithium ion storage and beyond.

High-Performance Lithium-Ion Storage of FeTiO3 with Morphology Adjustment and Niobium Doping.

Ferrous titanate (FeTiO3) has a high theoretical capacity and physical and chemical properties stability, so it is a potential lithium anode material. In this study, FeTiO3 nanopowder and nanosheets were prepared by the sol–gel method and the hydrothermal method. In addition, niobium-ion doping was carried out, the radius of Nb close to Ti so the Nb can easily enter into the FeTiO3 lattice. Nb can provide more free electrons to improve the electrochemical performance. Then, the effects of the morphology and niobium doping on the microstructure and electrochemical properties of FeTiO3 were systematically studied. The results show that FeTiO3 nanosheets have a better lithium storage performance than nanopowders because of its high specific surface area. A certain amount of niobium doping can improve the electrochemical performance of FeTiO3. Finally, a 1 mol% niobium-doping FeTiO3 nanosheets (1Nb-FTO-S) electrode provided a higher specific capacity of 782.1 mAh g−1 at 50 mA g−1. After 200 cycles, the specific capacity of the 1Nb-FTO-S electrode remained at 509.6 mAh g−1. It is revealed that an increased specific surface area and ion doping are effective means to change the performance of lithium, and the proposed method looks promising for the design of other inorganic oxide electrode materials.

Conductive-free Zn2GeO4 @multi-walled carbon nanotubes for high-performance lithium-ion storage

A new composite of Zn2GeO4 @multi-walled carbon nanotubes (Zn2GeO4 @MWCNTs) has been synthesized by using a facial microwave assisted hydrothermal method, and found that the Zn2GeO4 nanorods were anchored on the surface of MWCNTs and embedded into the voids of MWCNTs aggregation, which could provide a conductive network for fast transport of ion and a buffer space for volumetric change during the charge-discharge process. The MWCNTs in the composite has also acted as conductive agent, avoiding the use of additional conductive agents. When used as an anode for LIBs, this composite delivered a high specific capacity of 1397.9 mA h g−1 at 0.2 A g−1 after 300 cycles, an excellent rate capability and long cycling stability over1800 cycles at a high rate of 1.0 A g−1. The results of in situ X-ray diffraction (XRD) measurements showed that the Li22Ge5 was formed during the discharge process, and others were amorphous phase, which can provide more active sites for lithium storage, and is beneficial to the fast diffusion of lithium ion, resulting in superb cycling performance.