High-performance Lithium-ion Battery Anodes Research Articles

Carbon coating and oxygen vacancies render superior Li-ion storage of crystalline Ta2O5 by enhanced pseudocapacitance

Tantalum pentoxide (Ta2O5) possesses enormous potentials as high-performance anodes for lithium-ion batteries owing to its high specific capacity and abundant sources. Herein, various crystalline Ta2O5 nanomaterials were fabricated by annealing the precursors of (NH4)2Ta2O3F6 mesocrystals or polydopamine coated (NH4)2Ta2O3F6 composites in Ar or air atmospheres, which were synthesized with a hydrothermal process and followed the in-situ coating of polydopamine in aqueous solution. Particularly, the products obtained in Ar possess abundant oxygen vacancies. When evaluated as anodes for LIBs, Ta2O5@C-Ar with carbon coating and oxygen vacancies exhibits superior lithium storage properties including remarkably high reversible capacity, high rate capability (166 mAh g−1 at 2 A g−1), and excellent cyclic stability (up to 1000 cycles at 1 A g−1 with 0.02% capacity fading per cycle), in comparison with Ta2O5-Ar and Ta2O5-Air electrodes. Kinetics analysis based on cyclic voltammograms (CVs) discloses that the higher lithium storage capacity and superior rate capability of Ta2O5@C-Ar are primarily attributed to fast surface capacitive kinetics, which stem from large active surface area, ultrasmall Ta2O5 nanosheets with conductive carbon layer, and abundant oxygen vacancies. This strategy of constructing electrode materials with conductive carbon coating and oxygen vacancies provides a promising avenue for engineering advanced anodes with high specific capacity and excellent rate capability.

Core-shell structured Si@Cu nanoparticles encapsulated in carbon cages as high-performance lithium-ion battery anodes

Rationally surface optimization is considered to improve both energy capacity and structure stability in rechargeable batteries. A novel structure of copper coated silicon nanoparticles encapsulated in carbon cages (Si@Cu@CC) is synthesized by feasible methods of reduction and pyrolysis. The obtained composite exhibits a superior reversible capacity of 1724.3 mAh g−1 after 50 cycles at 0.1 A g−1, and the coulombic efficiency (CE) is 98.13%. It also maintains 1201.6 mAh g−1 even at the current density of 2 A g−1. The copper shell as a mechanical support layer wraps around the silicon nanoparticle can relieve the inner stress caused by the volumetric change. The exterior of Si@Cu particles is continuous network of carbon cages, which not only improves the conductivity of electrodes but also provides abundant transport channels for electrons and ions. The particular structure and the synergistic effect of copper and carbon have very important influence on the gorgeous properties of this composites.

A submicron Si@C core-shell intertwined with carbon nanowires and graphene nanosheet as a high-performance anode material for lithium ion battery

Silicon is widely used as anode for lithium-ion batteries (LIBs). However, its application is limited due to some problems such as large volume expansion. In this work, silicon waste from wafer slicing via diamond wire saw technology in photovoltaic industry is used as raw materials. A submicron core-shell structure Si@C intertwined with CNWs and graphene nanosheet, is prepared as anode for LIBs by hydrothermal process. The anode retains a specific capacity of 2514.8 mAh g−1 with capacity retention of 75.8% after 360 cycles under a current of 0.1 C and 1548.9 mAh g−1 after 1000 cycles under 0.2 C. In addition, it maintains 1596.9 mAh g−1 (1.0 C), 925.3 mAh g−1 (2.0 C) after several rate testing of 0.1 C to 2.0 C. A COMSOL Multiphysics and MD simulation are performed to examine the lithiation-induced volume expansion of silicon. The results demonstrate that, the lamellar micron silicon can achieve a stable lithium intercalating capacity larger than 2100 mAh g−1, which agrees well with our experimental results. It is demonstrated that the submicron Si from the kerf waste in the photovoltaic slicing process via diamond wire saw technology are available as direct raw materials for high performance anode of LIBs.

Sunflower seed husk-derived submicron carbon spheres and SnO2 nanoparticles composite used as an anode for high-performance lithium-ion batteries

Tin dioxide (SnO2) has a wide range of sources and high specific capacity, it is a forward-looking measure to use it as a lithium-ion battery anode, whereas its performance will hampered rapidly due to large volume expansion in practical applications. In this paper, based on the concept of environmental protection and green experiment, sunflower seed shell was used as raw material, biomass carbon microspheres were synthesized by hydrothermal method, and compounded with SnO2 nanoparticles in a certain proportion. Green biomass-derived carbon submicron spheres and their cross-linked structures can not only shorten the lithium ion transport path, but also reduce the structural damage caused by lithium ion intercalation. In particular, under the premise of carefully controlling the reaction time, those obtained after the reaction time for 24 h presented a promising Li storage properties and electrochemical performance with an excellent high-rate cycling stability of 590.5 mAh g−1 at 1C after 150 cycles. And it can still charge and discharge stably after 100 cycles at 0.2C and has a remarkable specific capacity of 959.2 mA h g−1.

Encapsulating homogenous ultra-fine SnO2/TiO2 particles into carbon nanofibers through electrospinning as high-performance anodes for lithium-ion batteries

Homogenous ultra-fine SnO2/TiO2 particles encapsulated into carbon nanofibers (SnO2/TiO2@CNFs) with a uniform and ordered one-dimensional fibrous structure are fabricated through facile electrospinning technique and subsequent heat treatments, which are confirmed by XRD, Raman, TG, SEM, TEM, and XPS analyses. The battery performance reveals that the SnO2/TiO2@CNFs-1.5:1 (1.5:1 denotes the mole ratio of SnO2 to TiO2 in the carbon nanofibers) electrode displays the optimal electrochemical properties among the whole samples, which can deliver the initial charge and discharge specific capacity of 1061.2 and 1494.8 mAh/g with a coulombic efficiency of 71.0% at 100 mA/g, and exhibit a remarkable specific capacity of 766.1 mAh/g after 200 cycles. Moreover, the SnO2/TiO2@CNFs-1.5:1 electrode displays a high pseudocapacitive contribution of 73.9% at the scan rate of 2 mV/s and the lithium ion diffusion coefficient of approximately 1.20 × 10−15 cm2 s−1. The excellent electrochemical performance of the SnO2/TiO2@CNFs-1.5:1 electrode is closely correlated with the synergetic effect of the proper amount of TiO2 that enhances the electrochemical stability of the electrode and provides fractional capacity, and the flexible and conductive carbon nanofiber matrix that accommodates volume changes and increases overall electronic conductivity. The detailed investigations of the as-prepared electrode materials by a facile electrospinning process may pave possible instructions for the next generation SnO2-based anodes and other related electrospun anodes for the energy storage device.

Solution-Grown Phosphorus-Hyperdoped Silicon Nanowires/Carbon Nanotube Bilayer Fabric as a High-Performance Lithium-Ion Battery Anode

The solution synthetic method can produce large quantities of silicon nanowires (SiNWs) for various applications, such as energy storage, texturing and composites materials, etc. However, solution-...

Core–Shell Structure of a Polypyrrole-Coated Phosphorus/Carbon Nanotube Anode for High-Performance Lithium-Ion Batteries

Black phosphorus is regarded as a promising anode material due to its high theoretical specific capacity and fast-charging safety compared with the commercial graphite-based anode materials. Howeve...

Pencil lead powder as a cost-effective and high-performance graphite-silica composite anode for high performance lithium-ion batteries

A facile method has been demonstrated in this research to prepare a graphite/silica composite anode from pencil needle powder. The obtained pencil needle powder is well characterized using X-ray diffraction, Raman spectroscopy, field emission scanning electron microscope, and high-resolution transmission electron microscope. The 4B pencil lead electrode outperformed graphite delivering a high specific capacity of 501 mAh g−1 after 100 cycles of galvanostatic charge-discharge at 100 mAg−1 current density. Further, the material has shown excellent specific capacities at various current densities. Furthermore, we elucidated the reaction mechanism taking place at the pencil electrode interface with density functional theory and post SEM and EDX analysis of the electrode. The outstanding anode performance is mainly due to the synergy of graphite/SiO2 composite where silica is also being converted to a stable fluorinated solid electrolyte interface (SEI) on the electrode surface. To check the commercial applicability of the inexpensive electrode, a comparative study has been made with commercially available cathodes like lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxide (NMC). Excellent cyclic stability with high discharge capacities observed during galvanostatic charge-discharge confirms the potential use of such electrodes for high performance and low-cost Li-ion batteries.

Co3 O4 Polyhedron@MnO2 Nanotube Composite as Anode for High-Performance Lithium-Ion Batteries.

In this work, a novel lollipop nanostructure of Co3 O4 @MnO2 composite is prepared as anode material in lithium-ion batteries (LIBs). Cobalt metal-organic framework (ZIF-67) is grown on the open end of MnO2 nanotubes via a self-assembly process. The obtained ZIF-67@MnO2 is then converted to Co3 O4 @MnO2 by a simple annealing treatment in air. Scanning electron microscopy, transmission electron microscopy, and X-ray diffraction characterizations indicate that the prepared Co3 O4 @MnO2 takes a lollipop nanostructure with a stick of ≈100nm in diameter, consisting of MnO2 nanotube, and a head part of ≈1µm, consisting of Co3 O4 nanoparticles. The charge-discharge tests illustrate that this unique novel configuration endows the resulting Co3 O4 @MnO2 with excellent electrochemical performances, delivering a capacity of 1080mAh g-1 at 300mA g-1 after 160 cycles, and 696mAh g-1 at 1 A g-1 after 210 cycles, compared with 404mAh g-1 and 590 for pure Co3 O4 polyhedrons and pure MnO2 nanotubes at 300mA g-1 after 160 cycles, respectively. The lollipop configuration consisting of porous Co3 O4 polyhedron and MnO2 nanotube shows excellent structural stability and facilitates lithium insertion/extraction, leading to excellent cyclic stability and rate capacity of Co3 O4 @MnO2 -based LIBs.

Enhancing the performance of manganous oxide nanoparticles for lithium storage by in-situ construction of porous carbon embedment

Although having high theoretical capacity, manganous oxide (MnO) still faces challenges for application in anodes of lithium-ion batteries because of its notorious shortcomings such as enormous volume change and poor conductivity. Herein, a facile and relatively green strategy has been demonstrated to efficiently mitigate above issues, that is, in-situ embedding MnO nanoparticles into a porous carbon matrix by a NaCl template method. The well-designed porous carbon matrix enhances not only conductivity but also structural stability of the as-prepared MnO/C composite electrode during cyclic charge/discharge process. As a consequence, this MnO/C composite, evaluated as an anode of lithium-ion batteries, shows improved performance with 1501 and 1277 mAh g−1 after 180 and 250 cycles at 200 and even 1000 mA g−1, respectively. Moreover, this effective strategy may increase the margin of facile and green preparation of other high-performance metal oxide-based anodes for lithium-ion batteries.

Ionic liquid-induced ultrathin and uniform N-doped carbon-wrapped T-Nb2O5 microsphere anode for high-performance lithium-ion battery

Orthorhombic-phase Nb2O5 (T-Nb2O5) has been widely investigated as an intercalation anode material for Li-ion batteries due to the larger interplanar lattice spacing and high safety. However, its applications are limited by the intrinsic low electric conductivity. Herein, an ultrathin N-doped carbon-coating layer was constructed on porous T-Nb2O5 microspheres uniformly via a convenient thermal treatment method with ionic liquid as a carbon precursor. The synthesized T-Nb2O5@N–C exhibits significantly enhanced rate capability (155.5 mAh·g–1 at 20C) than initial T-Nb2O5 (110.2 mAh·g–1 at 20C). Besides, T-Nb2O5@N–C shows ultralong cycle life, with only a 0.02% decrease in the capacity per cycle at a high current density of 10C. The corresponding electrochemical tests show that the preferable rate capability of T-Nb2O5@N–C electrode is attributed to the increased electronic conductivity and pseudocapacitance contribution induced by ultrathin surface N-doped carbon layer. On the other hand, the mesoporous structure of T-Nb2O5@N–C ensures fast Li+ diffusion dynamics and electrolyte penetration. Furthermore, T-Nb2O5@N–C also performs well in a LiNi0.5Mn0.3Co0.2O4||T-Nb2O5@N–C full cell. This work provides a facile method to construct integrated anode materials for potential applications in lithium-ion batteries.

Facile preparation of hierarchical CuO nanostructures as a integrate binder-free anode for high-performance lithium-ion batteries

Novel CuO hybrid nanostructures composed of one-dimensional (ID) porous carbon nanofibers and two-dimensional (2D) graphene nanosheets have been fabricated with the help of electrospinning technique, which is denoted as CuO@PCNF/GN. The microstructure and morphology of the CuO@PCNF/GN were investigated by X-ray diffraction and transmission electron microscopy. The electrochemical performances of the as-prepared materials as a novel bind-free anode for lithium ion battery (LIB) were investigated. The CuO@PCNF/GN electrode exhibited high discharge capacity of 665 mAh g−1 after 60 cycles at the current density of 100 mA g−1. Even at 800 mA g−1, the discharge capacity of the anode could still maintained at 443 mAh g−1. The excellent electrochemical properties of CuO are greatly related to the unique 3D interconnected structure of continuous PCNF and GN, which enables efficient electron/ion transport and migrate the volume change of active CuO materials.

Depositing natural stibnite on 3D TiO2 nanotube array networks as high-performance thin-film anode for lithium-ion batteries

Three-dimensional (3D) thin-film electrodes are promising solution to the volume change of active materials in lithium-ion batteries. As a conductive current collector, the 3D TiO2 nanotube array networks (TNAs) have a one-dimensional stable electronic conductive path and increase the adhesion between the current collector and raw material, thereby improving the cycle stability of active materials. In this study, a novel 3D-TNAs@Sb2S3 anode was fabricated by directly depositing natural stibnite onto 3D TNAs. The adhesion of Sb2S3 particles to the substrate was enhanced due to the large surface area provided by 3D-TNAs. Moreover, the porous layered structure composed of Sb2S3 nanoparticles relieved the stress generated during lithiation and adapted to the volume change of Sb2S3 during cycling. Therefore, the resulting composite anode exhibits high cycle and rate performance, reaching 0.36 mAh·cm−2 after 80 cycles at the galvanostatic rate of 1 mA·cm−2, with high coulombic efficiency of 98%.

Porous N-doped C coated gallium nitride submicron bricks/reduced graphene oxide hybrid as high-performance anode for lithium-ion batteries

Porous architecture of N-doped carbon coated gallium nitride sub-micrometer bricks comprising of nanoscale carbon-coating primary nanoparticles/reduced graphene oxide hybrids (GaN–NC–RGO) are firstly designed as high-performance anode for lithium-ion batteries (LIBs). The GaN–NC–RGO electrode shows excellent electrochemical performance, with the integral porous architecture and the GaN nanoparticles enhancing the reaction activity, the nanoscale NC coating and the microscale RGO hybridization facilitating electron transfer, and the submicron size of the GaN bricks improving the tap density. The GaN–NC–RGO electrode delivers high discharge capacity of 398.6 mAh g−1 after 550 cycles at 0.05 A g−1, and this value increases to 445.4 mAh g−1 at 0.02 A g−1. After 5 periodic rate capability testing over 400 cycles, the discharge capacity of the GaN–NC–RGO electrode can be fully recovered when reverting current to 0.05 A g−1. The feasible electrode design strategy coupled with the facile fabrication approach and the impressive performances of the GaN–NC–RGO electrode may be referential for the development of high-performance GaN-based materials for LIBs.

Cowpea-like N-Doped Silicon Oxycarbide/Carbon Nanofibers as Anodes for High-Performance Lithium-Ion Batteries

Silicon oxycarbide (SiOC) is considered as a potential anode material in lithium-ion batteries because of its high theoretical capacity and good structural stability. Despite many such assets, its ...

High-performance Si/nano-Cu/CNTs/C anode derived from photovoltaic silicon waste: A potential photovoltaic-energy storage strategy

The growing photovoltaic industry produces a mass of silicon cutting waste each year. How to effectively manage the resulting silicon cutting waste is essential from an environmental and an economic perspective. In this study, a new strategy was developed to utilize silicon cutting waste and fabricate high-performance lithium-ion battery anode materials. This study combines nanocopper-assisted chemical etching technology with graphite and carbon nanotubes (CNTs) coating technology. The resulting Si/nano-Cu/CNTs/C composite show an excellent reversible capacity of 1750 mAh/g and 64% capacity retention rate after 100 cycles at 200 mA/g. Different current charging and discharging tests were applied, and good rate performance achieved. When the current was switched from 2000 mA/g to 100 mA/g, the discharge capacity returned to the original 1750 mAh/g, demonstrating excellent rate performance. Furthermore, the higher ion diffusion coefficient improved the conductivity of the electrode, and the combination of silicon and carbon is beneficial to the electrode stability, which was verified by simulation calculation. Our work indicates that the silicon waste can be a cost-effective silicon source in the preparation of high-performance Si/C anode material by the simple and economical manufacturing method.

Urchin-like MnO/C microspheres as high-performance lithium-ion battery anode

Manganese oxide (MnO) is prospective as anode material for lithium-ion batteries (LIBs) due to its low insertion voltage and high reversible capacity. Here, urchin-like MnO microspheres with carbon coating (u-MnO/C) are synthesized through hydrothermal method, and its lithium storage performance is investigated. The unique urchin-like structures of u-MnO/C endow it high surface area which provides sufficient contact with electrolyte. The carbon coating can effectively suffer volume change of u-MnO during charge/discharge process. Meanwhile, the carbon coating can effectively improve the conductivity of u-MnO-based anode. Due to the above features, u-MnO/C delivers high initial capacity of 845 mAh g−1, and an obvious activation process is observed at the beginning of the cycles thanks to the abundant invasion of the electrolyte into u-MnO/C. The large capacity of 723 mAh g-1 can still be achieved after 80 cycles. This work provides a promising guide for designing high-performance LIBs electrode materials.

A Covalent P-C Bond Stabilizes Red Phosphorus in an Engineered Carbon Host for High-Performance Lithium-Ion Battery Anodes.

The red phosphorus (RP) anode has attracted great attention due to its high theoretical specific capacity (2596 mAh/g) and suitable lithiation potential. To solve the inherent poor electrical conductivity and the large volume expansion due to the lithiation process, a vaporization-condensation strategy is considered as a promising method. However, there are two important issues that deserve attention in the vaporization-condensation process. First, the low P mass loading in the carbon-based frameworks (∼30 wt %) limits the energy density. Second, a residual white phosphorus (WP) leads to the safety problems of flammability and high toxicity. Herein, we found that the edge structure of carbon framework can offer the strong adsorption for P4 and form a P-C bond, which accelerate the adsorption and polymerization of P4 leading to high P mass loading and safety. When the porous carbon (PC) with plenty of edge carbons was used as the matrix to load P by vaporization-condensation, the RP loading is close to the highest theoretical mass loading of ∼50 wt % calculated based on the feeding ratio of RP/PC = 1/1. Therefore, the RP-PC anode provides a high specific capacity of 965.2 mAh/g even after 1100 cycles at 1000 mA/g (equivalent to 1 C) and a high-rate capacity of 496.8 mAh/g at 8320 mA/g (equivalent to 16.7 C) after 1000 cycles (the specific capacity and current density are calculated based on the total weight of RP and PC).

Characteristics and electrochemical performances of silicon/carbon nanofiber/graphene composite films as anode materials for binder-free lithium-ion batteries

We report the interfacial study of a silicon/carbon nanofiber/graphene composite as a potentially high-performance anode for rechargeable lithium-ion batteries (LIBs). Silicon nanoparticle (Si)/carbon nanofiber (CNF)/reduced graphene oxide (rGO) composite films were prepared by simple physical filtration and an environmentally-friendly thermal reduction treatment. The films were used as high-performance anode materials for self-supporting, binder-free LIBs. Reducing graphene oxide improves the electron conductivity and adjusts to the volume change during repeated charge/discharge processes. CNFs can help maintain the structural stability and prevent the peeling off of silicon nanoparticles from the electrodes. When the fabricated Si/CNF/rGO composites were used as anodes of LIBs, the initial specific capacity was measured to be 1894.54 mAh/g at a current density of 0.1 A/g. After 100 cycles, the reversible specific capacity was maintained at 964.68 mAh/g, and the coulombic efficiency could reach 93.8% at the same current density. The Si/CNF/rGO composite electrode exhibited a higher specific capacity and cycle stability than an Si/rGO composite electrode. The Si/CNF/rGO composite films can effectively accommodate and buffer changes in the volume of silicon nanoparticles, form a stable solid–electrolyte interface, improve the conductivity of the electrode, and provide a fast and efficient channel for electron and ion transport.

Sulfur- and nitrogen-doped rice husk-derived C/SiOx composites as high-performance lithium-ion battery anodes

To enhance the comprehensive utilization of agricultural waste in new energy materials, sulfur/nitrogen dual-doped porous C/SiOx composites (SN@C/SiOx) are successfully prepared via a facile and economical method. In this approach, rice husks are used as the C and Si source and thiourea as the S and N source. This SN@C/SiOx composite possesses a high specific surface area and SiOx particles are evenly distributed in the S/N-doped C matrix. The S/N-doped C matrix not only improves electrical conductivity and impedes the agglutination of particles, but also buffers the volume variation of SiOx, achieving enhanced electrochemical properties. As a lithium-ion battery (LIBs) anode, the as-synthesized SN@C/SiOx composite delivers an impressive specific capacity (1150 mAh/g) and enhanced initial coulombic efficiency (CE) of 70.4%. Even at a large current density of 1.0 A/g, the reversible capacity remains 632 mAh/g after 1200 cycles. This doping carbonization strategy offers the potential for using rice husks in the development of high-performance lithium ion batteries.