Superior Lithium Storage Research Articles

Snake-like ZnO nanorods encapsulated by carbon shell self-assembled on the porous N-doped carbon nanocages with Co3O4 and ZnO nanoparticles embedded for superior lithium storage

The exploration of electrode materials with improved performance is continuously at the forefront of lithium ion storage research. Through calcination in an argon atmosphere after stirring the glucose with MOF precursors, we can effectively obtain the ZnO/Co3O4@NC@R-1-0.1 composite. It can be observed that ZnO and Co3O4 nanoparticles are uniformly embedded in the N-doped porous carbon nanocages without any aggregation and the snake-like ZnO nanorods with special core-shell structure self-assemble on the surface of the nanocages. To the best of our knowledge, it has been firstly reported that ZnO exhibits the appearance of snake-like nanorods in the composite. Meanwhile, the size and number of the snake-shaped nanorods can be effectively adjusted by changing the amount of glucose. When tested as electrode materials in LIBs, the materials with unique hierarchical structures demonstrated remarkable superior lithium-storage capacity and cycling stability (958 mA h g-1 at 2 A g-1 after 1500 cycles).

Poplar branch bio-template synthesis of mesoporous hollow Co3O4 hierarchical architecture as an anode for long-life lithium ion batteries

Mesoporous hollow hierarchical structures play an important role in enhancing the lithium storage performances of Co3O4 anode materials. In this work, Co3O4 with mesoporous hollow structure has been successfully fabricated by simple impregnation and subsequently air calcination using poplar branch as bio-template. The product calcined at 600 °C (PB-Co600) perfectly duplicates the 3D aligned microchannels structure of poplar branch. Importantly, the wall of aligned microchannels in PB-Co600 is constructed by a lot of irregular cross-linked Co3O4 nanoparticles and there are abundant mesopores on the surface. As an anode, it exhibits high reversible capacity and remarkable long-cycle stability. At 0.1 A g-1, it can deliver a high specific capacity of 1153.7 mA h g-1 after 100 cycles, and even at 1 A g-1, the reversible specific capacity of 555.7 mA h g-1 can be retained after cycling 1000 times. The excellent lithium storage performance of PB-Co600 may be attributed to its unique hierarchical structure, which is not only favorable to the rapid transfer of substances and Li+ ion diffusion, but also alleviates the volume change during the charge/discharge cycle. Furthermore, the existence of oxygen vacancies and pseudo-capacitance also contributes significantly to the superior lithium storage performance of the PB-Co600 electrode. Therefore, the PB-Co600 prepared by a large-scale and eco-friendly route can be used as a potential candidate anode for LIBs.

Metal nanodots anchored on carbon nanotubes prepared by a facile solid-state redox strategy for superior lithium storage

Alloying-based electrode materials (e.g. Si, Sn, Sb, Bi, etc.) are the promising anode candidates for next-generation lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) owing to their high specific capacities, but they suffer from huge volume changes upon lithium/sodium insertion/extraction processes. On the other hand, such alloying anodes usually require a complicated and high energy-consumption synthesis process (e.g. Si anode by a magnesiothermic reduction at over [Formula: see text]C, Sn, Sb and Bi anodes by a high-temperature carbothermic reduction at 600–[Formula: see text]C), thus limiting their practical application for replacing low-cost graphite. In this work, we develop a straightforward solid-state strategy for a general synthesis of metal nanodots (Sn, Sb and Bi) supported on carbon nanotubes (CNTs) by using the reduction potential differences of metal salts and NaBH4 as the reaction power at room temperature. Owing to the very mild reaction, the resulted active component is small enough (2–5[Formula: see text]nm) with diffusion-less and nucleation-less barriers upon alloying/dealloying reaction, thus enabling high electrode stability and high capacity retention. Taking Sn anode as an example, the obtained Sn/CNTs deliver a high reversible capacity of 415[Formula: see text]mAh g[Formula: see text] at 0.5[Formula: see text]A g[Formula: see text] after 1000 cycles without obvious capacity decay. Such findings indicate that the proposed solid-state synthetic method could offer a great potential for realizing large-scale and economic applications of energy storage materials.

Dual carbon protected SnO2 with superior lithium storage performance

Due to the high theoretical capacity, SnO2 was considered as a prospective anode for the new-generation lithium-ion batteries. Here, a novel dual carbon protection strategy for fabricating a carbon-based framework for SnO2 materials, in which the SnO2 nanoparticles were encapsulated in the N-doped carbon and well decorared on a macroporous graphene framework (NC@SnO2/G). As an anode, the CN@SnO2/G exhibits preferable energy storage properties compared with the pure SnO2 and SnO2/graphene. The NC@SnO2/G delivers not only a higher capacity of 974.9 mAh g−1 at 0.5 A g−1 (350 cycles), but also an excellent rate capability of 418.1 mAh g−1 even at 3 A g−1. Such superb performance could be assigned to the nanosize of SnO2 decrease the ions transport length and increase active sites, the macroporous graphene framework faciliate the electrolyte penetration and buffer volumne change, the N-doped carbon coating could facilitate formation stable solid electrolyte interface (SEI), prevent the imtermediate Sn agglomeration, and improve the conductivity. This work could be extended to other metal oxide/carbon composites with high energy storage performance.

Synergistic effect from coaxially integrated CNTs@MoS2/MoO2 composite enables fast and stable lithium storage

Molybdenum oxide/sulfide materials are extensively evaluated as high-capacity anode candidates for lithium ion batteries. However, they suffer from rapid capacity decay and poor kinetics. Herein, we report on synergistic effect from structurally integrated coaxial [email protected]2/MoO2 composite material on lithium storage, in which MoS2/MoO2 nanosheets are conformally decorated on carbon nanotubes (CNTs). In-situ synchrotron X-ray diffraction measurement is performed to elucidate synergistic effect among three MoS2, MoO2 and CNTs components for lithium storage. Reaction mechanism exploration reveals that the MoO2 component undergoes reversible Li+ intercalation via forming a stable Li0.98MoO2 phase over a voltage range of 3.0 to 0.01 V vs. Li+/Li, without experiencing the conversion reaction into metallic Mo, which contributes to long-term stability during charge/discharge cycles. Meanwhile, lithium storage of MoS2 is through lithium and sulfur reversible reaction after the initial conversion reaction of lithiated MoS2 forming Li2S and Mo. The CNTs component enhances electronic conductivity and structural stability by minimizing volume change and reaction strains in the [email protected]2/MoO2 composite anode. A desired 68.2% capacity retention upon 2000 cycles at 10 A/g has been demonstrated for the [email protected]2/MoO2 anode, revealing prominent reaction kinetics and structural stability for fast and stable lithium storage, superior to various Mo-based anode materials previously reported. The findings from this study, with the unique insight into the role of structural integrity in combining MoS2/MoO2 materials with the CNTs substrate, offers a strategy for designing composite anode materials for superior lithium storage performance.

Hierarchical Design of Mn2P Nanoparticles Embedded in N,P-Codoped Porous Carbon Nanosheets Enables Highly Durable Lithium Storage.

Although transition metal phosphide anodes possess high theoretical capacities, their inferior electronic conductivities and drastic volume variations during cycling lead to poor rate capability and rapid capacity fading. To simultaneously overcome these issues, we report a hierarchical heterostructure consisting of isolated Mn2P nanoparticles embedded into nitrogen- and phosphorus-codoped porous carbon nanosheets (denoted as Mn2P@NPC) as a viable anode for lithium-ion batteries (LIBs). The resulting Mn2P@NPC design manifests outstanding electrochemical performances, namely, high reversible capacity (598 mA h g-1 after 300 cycles at 0.1 A g-1 ), exceptional rate capability (347 mA h g-1 at 4 A g-1), and excellent cycling stability (99% capacity retention at 4 A g-1 after 2000 cycles). The robust structure stability of Mn2P@NPC electrode during cycling has been revealed by the in situ and ex situ transmission electron microscopy (TEM) characterizations, giving rise to long-term cyclability. Using in situ selected area electron diffraction and ex situ high-resolution TEM studies, we have unraveled the dominant lithium storage mechanism and confirmed that the superior lithium storage performance of Mn2P@NPC originated from the reversible conversion reaction. Furthermore, the prelithiated Mn2P@NPC∥LiFePO4 full cell exhibits impressive rate capability and cycling stability. This work introduces the potential for engineering high-performance anodes for next-generation high-energy-density LIBs.

Zn/Co-ZIF-derived bi-metal embedded N-doped porous carbon as anodes for lithium-ion batteries

In this work, the unique Zn-Co nitrogen-doped porous carbon (Zn-Co/NPC) polyhedrons have been successfully synthesized via pyrolysis of bimetallic zeolitic imidazolate frameworks (ZIFs) precursor under N2, wherein the metallic Co and Zn particles are dispersed in the porous carbon matrix. The obtained porous carbons show a high surface area (315.67 m2 g−1) and contain plenty of mesopores. The unique mesoporous structure benefits from either the carbonization of organic ligands and the catalytic effect of metallic Co in calcination process or the elimination of a certain amount of metal species in acid dissolution. As an anode material for lithium-ion batteries, the Zn-Co/NPC particles exhibit superior lithium storage capabilities with excellent cycling properties. It demonstrates a high discharge capacity of 970 mA h g−1 at 0.1 A g−1. Besides, a reversible capacity of 813.5 mA h g−1 was retained at a much higher current density of 0.5 A g−1 after 500 cycles. The enhanced electrochemical performance was attributed to the unique microstructure, nitrogen doping, and the synergistic effect of Zn and Co embedded in carbon matrix.

Study on the superior lithium storage performance of carbon/Sn–Mo oxide composite as lithium-ion battery anode

A facile generic solvothermal strategy is employed to prepare C/SnOx/MoOy composite with evenly distributed C, Sn, Mo and O elements. The multi-element characteristic of active components and the introduction of carbon phase contribute greatly to the improved electrochemical performance as LIBs anodes. The influence of carbon phase and content of Sn and Mo on electrochemical behavior were investigated in this work. Carbon phase contributes greatly to the enhanced electric conductivity, structural integrity and pseudocapacitance contribution of the electrode. The best electrochemical performance is achieved in carbon/Sn–Mo oxide anode with a Sn/Mo ratio of about 1:1, indicating the mutual buffering relationship between Sn and Mo due to the different working voltage toward lithium. As a result, an excellent capacity retention of 98% (vs 2nd cycle) is delivered after 500 cycles at 0.5 A g−1. Even at a high rate of 2.0 A g−1, the capacity could be well remained after 500 cycles. Moreover, full cell employing such a C/SnOx/MoOy anode in combination with LiCoO2 cathode offers a good cycling performance.

Facile synthesis of carbon embedded dual phase MnO/MnS nanoparticles composite for superior lithium storage performance

Herein, carbon embedded dual phase MnO/MnS nanoparticles (MnO/MnS-C) composite was synthesized through a facile one-step solvethermal method and subsequent heat treatment. Applied to lithium ion batteries anode, the MnO/MnS-C electrode exhibits a high reversible specific capacity (1183 mAh/g at 0.2 A/g after 240 cycles) and an excellent high-rate cycling stability (783 mAh/g at 0.5 A/g after 300 cycles). The superior lithium storage performance of the MnO/MnS-C is mainly ascribed to the presence of carbon matrix, which can not only stabilize the MnS/MnO nanoparticles against self-agglomeration and buffer the volume expansion of the MnS/MnO nanoparticles during lithiation/delithiation, but also enhances the conductivity of whole structure.

Spinel-structured high entropy oxide (FeCoNiCrMn)3O4 as anode towards superior lithium storage performance

High entropy oxide (HEO) is a new-type inorganic material composed of multiple principle metal elements with a single-phase structure and is proved to display many potential unexpected properties such as high structural stability and superionic conductivity. Herein, a novel spinel-structured high entropy oxide (FeCoNiCrMn)3O4 is prepared by high-temperature solid state reaction and evaluated as anode for lithium-ion batteries (LIBs). In-situ high-temperature X-ray diffraction (HT-XRD) is used to reveal structure evolution of mixed oxides with the calcination temperature increase and a single-phase spinel-structured (FeCoNiCrMn)3O4 is obtained at 900 °C. The effect of temperature on structure and electrochemical performance of HEO were investigated, and the HEO-900 anode with commercial mass loading exerts higher capacity (discharge/charge, 1034/680 mAh g−1) and better rate capability (182 mAh g−1 at 2 Ag-1) than HEO-950 and HEO-1000 for its moderate particle size, and all the three samples show excellent cycling stability. Ex-situ XRD and transmission electron microscope are applied to unravel the lithium-storage mechanism of (FeCoNiCrMn)3O4, an amorphization reaction process occurs during the initial discharging and the amorphous structure is maintained in subsequent cycles. The synergetic effect of multiple metal cations with different radius, valence states and reaction potentials and entropy stabilization effect make the HEO display a superior electrochemical performance in LIBs. This work provides a new concept to design multi-element transition metal oxide anode materials by high entropy strategy.

Phase inversion synthesis of Fe3O4@NC composites with superior lithium storage performance

The N-doped carbon coated Fe3O4 composites (Fe3O4@NC) are successfully fabricated on a polyacrylonitrile (PAN) phase inversion method and subsequently annealing. Compared with common electrospinning method, needing delicate equipment and strict reaction conditions, this method is facile and ingenious to synthesize PAN-based composites or carbon-coated materials. Applied to lithium ion batteries (LIBs) anode, the Fe3O4@NC composite exhibits a large specific capacity of 981 mAh g−1 at 0.2 A g−1 after 500 cycles, an outstanding rate capability and a superior long-term high-rate cycling performance (632 mAh g−1 at 1 A g−1 after 900 cycles). Its excellent electrochemical performance is attributed to the thin carbon layers on the surface of Fe3O4 nanoparticles, which can not only enhance the electron conductivity, but also buffer the volume change of Fe3O4 nanoparticles during lithiation/delithiation. Moreover, the doped nitrogen atoms derived from PAN can lead to more defects in electrode material, which benefits to the electrochemical performance of Fe3O4@NC composites.

3D graphene-like nanosheets/silicon wrapped by catalytic graphite as a superior lithium storage anode

Silicon–carbon composites, which exhibit the advantages of both carbon and silicon materials, are regarded as the most promising anode for lithium ion battery. In this work, a composite of 3D graphene-like nanosheets/silicon wrapped by catalytic graphite (G-3DGNs-Si) was prepared via a chemical oxidation–thermal expansion strategy and high-temperature sintering method. The obvious interlinked 3D-layered spaces in 3DGNs arranged orderly can uniformly accommodate silicon nanoparticles (SiNPs). 3DGNs can relieve the volume expansion and improve the electrical conductivity of SiNPs. In addition, the catalytic graphite evenly coated on the 3DGNs-Si can further improve electrochemical performance. The G-3DGNs-Si composite anode can achieve 90% reversible capacity retention (957.2 mAh g−1) at 0.2 A g−1 after 100 cycles (78.9% after 300 cycles). The method is effective and easy to operate. This work provides a novel idea for designing silicon–carbon composites.

Free‐Standing Crystalline@Amorphous Core–Shell Nanoarrays for Efficient Energy Storage

Structures comprising high capacity active material are highly desirable in the development of advanced electrodes for energy storage devices. However, the structure degradation of such material still remains a challenge. The construction of amorphous and crystalline heterostructure appears to be a novel and effectual strategy to figure out the problem, owing to the distinct properties of the amorphous protective layer. Herein, crystalline-Co3 O4 @amorphous-TiO2 core-shell nanoarrays directly grown on the carbon cloth substrate are rationally designed to construct the free-standing electrode. In the unique structure, the 3D porous nanoarrays provide increased availability of electrochemical active sites, and the array with a unique heterostructure of crystalline Co3 O4 core and amorphous TiO2 shell exhibits intriguing synergistic properties. Besides, the amorphous TiO2 protective layer shows elastic behavior to mitigate the volume effect of Co3 O4 . Benefiting from these structural advantages, the as-prepared free-standing electrode exhibits superior lithium storage properties, including high coulombic efficiency, outstanding cyclic stability, and rate capability. Pouch cells with high flexibility are also fabricated and show remarkable electrochemical performances, holding great potential for flexible electronic devices in the future.

CNT-Assembled Octahedron Carbon-Encapsulated Cu3P/Cu Heterostructure by In Situ MOF-Derived Engineering for Superior Lithium Storage: Investigations by Experimental Implementation and First-Principles Calculation.

Conspicuously, metal–organic frameworks (MOFs) serve as homogenously and periodically atom‐dispersed self‐sacrificial template for in situ engineering of hierarchical porous carbon‐encapsulated micro/nanoheterostructure materials, integrating the merits of micro/nanostructure to high‐volumetric energy storage. Copper phosphide represents a promising candidate due to its compact material density compared to commercial graphite. Herein, micro/nanostructured Cu3P/Cu encapsulated by carbon‐nanotube‐assembled hierarchical octahedral carbonaceous matrix (Cu3P/Cu@CNHO) is constructed by an in situ MOF‐derived engineering for novel anode material in LIBs, which achieves an extraordinary cycling stability (a well‐maintained gravimetric/volumetric capacity of 463.2 mAh g−1/1878.4 mAh cm−3 at 1 A g−1 up to 1600 cycles) and distinguished rate capability (an ameliorated capacity of 317.7 mAh g−1 even at 10 A g−1), together with unprecedented heat‐resistant capability (an elevated temperature of 50 °C for 1000 cycles maintaining 434.7 mAh g−1 at 0.5 A g−1). The superior electrochemical performance of Cu3P/Cu@CNHO is credited to the large specific surface area, conductive carbon matrix and metallic copper dopants, synergistic effects of the intrinsic Cu3P/Cu heterostructure, and well‐defined micro/nanostructure, facilitating a boosted electrochemical conductivity and accelerated diffusion kinetics.

Binder-free and self-supported reduced graphene oxide coated Cu2SnS3/Carbon nanofibers for superior lithium storage

Abstract To utilize the nanomaterials that could be mass manufactured for energy storage, a self-supported reduced graphene oxide (rGO) coated Cu2SnS3 (CTS)/carbon nanofiber (CNF) electrode is fabricated by the facile gelation-solvothermal-electrodeposition method, and applied in lithium-ion batteries without a binder or conductive agent. Compared with the CTS microtubes synthesized from their complex template, the CTS nanoparticles in the rGO@CTS/CNF film are anchored on the CNF surface and surrounded by the conformal rGO with varying spacings. The whole self-supported rGO@CTS/CNF electrode (including the CNF and rGO) delivers an initial capacity of 678.8 mAh g−1 at 0.5 A g−1, and retains at 464.2 mAh g−1 after 200 cycles, which is superior to those of the pristine CTS microtubes and the uncoated CTS/CNF electrodes.

Preparation of promising anode materials with Sn-MOF as precursors for superior lithium and sodium storage

Abstract A facile low-temperature aqueous solution method was applied to synthesize Sn-MOF hexahedron, and then the SnO@C, Sn/SnO@C and Sn@C nanocomposites were obtained by H2 reduction using the Sn-MOF as a template at different temperatures. SnO and Sn are embedded in the hexahedral carbon framework with the form of nanorods and nanospheres, respectively. When utilized as anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), all the three materials exhibited superior electrochemical performance thanks to the regular hexahedral structure provided by MOFs. Notably, benefiting from the coexistence of rod-like SnO and sphere-like Sn, which is helpful to alleviate the aggregation effect of the sample, Sn/SnO@C exhibited the best rate performance (516.1 mA h g−1 for LIB and 130.1 mA h g−1 for SIB at the current density of 2000 mA g−1) and remarkable cyclability (835.9 mA h g−1 for LIB at 1000 mA g−1 after 200 cycles and 401.5 mA g−1 for SIB at 100 mA g−1 after 100 cycles). The results show that the Sn/SnO@C composite has potential as a practical anode for lithium ion batteries and sodium ion batteries.

Preparation and lithium storage performances of g-C3N4/Si nanocomposites as anode materials for lithium-ion battery

As the anode material of lithium-ion battery, silicon-based materials have a high theoretical capacity, but their volume changes greatly in the charging and discharging process. To ameliorate the volume expansion issue of silicon-based anode materials, g-C3N4/Si nanocomposites are prepared by using the magnesium thermal reduction technique. It is well known that g-C3N4/Si nanocomposites can not only improve the electronic transmission ability, but also ameliorate the physical properties of the material for adapting the stress and strain caused by the volume expansion of silicon in the lithiation and delithiation process. When g-C3N4/Si electrode is evaluated, the initial discharge capacity of g-C3N4/Si nanocomposites is as high as 1033.3 mAh/g at 0.1 A/g, and its reversible capacity is maintained at 548 mAh/g after 400 cycles. Meanwhile, the improved rate capability is achieved with a relatively high reversible specific capacity of 218 mAh/g at 2.0 A/g. The superior lithium storage performances benefit from the unique g-C3N4/Si nanostructure, which improves electroconductivity, reduces volume expansion, and accelerates lithium-ion transmission compared to pure silicon.

Selective Solid-Liquid Interface Sulfidation Growth of Hierarchical Copper Sulfide and Its Hybrid Nanoflakes for Superior Lithium-Ion Storage.

Two-dimensional metal sulfides and their hybrids are emerging as promising candidates in various areas. Yet, it remains challenging to synthesize high-quality 2D metal sulfides and their hybrids, especially iso-component hybrids, in a simple and controllable way. In this work, a low-temperature selective solid-liquid sulfidation growth method has been developed for the synthesis of CuS nanoflakes and their hybrids. CuS nanoflakes of about 20 nm thickness and co-component hybrids CuOx /CuS with variable composition ratios derived from different sulfidation time are obtained after the residual sulfur removal. Besides, benefiting from the mild low-temperature sulfidation conditions, selective sulfidation is realized between Cu and Fe to yield iso-component FeOx /CuS 2D nanoflakes of about 10-20 nm thickness, whose composition ratio is readily tunable by controlling the precursor. The as-synthesized FeOx /CuS nanoflakes demonstrate superior lithium storage performance (i. e., 707 mAh g-1 at 500 mA g-1 and 627 mAh g-1 at 1000 mA g-1 after 450 cycles) when tested as anode materials in LIBs owing to the advantages of the ultrathin 2D nanostructure as well as the lithiation volumetric strain self-reconstruction effect of the co-existing two phases during charging/discharging processes.

In situ construction of bamboo charcoal derived SiOx embedded in hierarchical porous carbon framework as stable anode material for superior lithium storage

Ongoing pursuit of high performance functional materials from natural and inexpensive resources receive continuous attention. 3D porous SiOx/C composites are constructed only from commercial bamboo charcoal via an in situ top-down synthetic route involving activated carbonization and mild aluminothermic reduction. Particularly, the obtained composites possess a well-reserved porous and hierarchical structure where SiOx nanoparticles are embedded in the entire 3D carbon framework. When used as the active material for lithium-ion battery anode, the optimized SC-3 sample achieves the impressive specific capacity (1100 mA h g−1) at 200 mA g−1 after 300 cycles, as well as prominent cyclic stability under 1 A g−1 (700 mA h g−1 after 200 cycles). Besides, this SiOx/C anode demonstrates perfect capacity retentions and superior cyclic stability in full cells. This low cost bamboo-derived composite can further broaden the vision of advancing new-generation anode materials for rechargeable batteries and the related hierarchical composites.

Phase-Controllable Cobalt Phosphides Induced through Hydrogel for Higher Lithium Storages.

Transition metal phosphides (TMPs) have gained increased attention in energy storage due to their potential applications for optimizing electrochemical performances. However, their preparation routes usually require highly toxic and flammable phosphorus sources with strict reaction conditions. The existence of multiple energetically favorable stoichiometries also makes it a challenge to achieve phase control of metal phosphides. In this work, we have successfully realized the phase-controllable framework of cobalt phosphide from Co2P to CoP by employing a semi-interpenetrating network (semi-IPN) hydrogel as a precursor. Interestingly, the semi-IPN hydrogel could serve as a self-assembly/sacrificing template to accomplish 3D space confinement, where poly(vinylphosphonic acid) (PVPA) was identified as a prominent phosphorus source due to its strong metal complexation ability and high thermal stability. Furthermore, this route is successfully extended to the synthesis of other TMPs, including Fe2P, Ni2P, and Cu3P. The specific structure of cobalt phosphides gives rise to superior lithium storage performance, showing superior cycling stability (495.2 mAh g-1 after 1000 cycles at 2.0 A g-1). This approach envisions a new outlook on exploitation of essential functional hydrogels for the creation of inorganic materials toward sustainable energy development.