High-capacity Anode Material For Lithium-ion Batteries Research Articles

Boron-doped porous waste silicon/carbon composite with improved performance for lithium-ion batteries

With the rapid development of the photovoltaic (PV) industry, the amount of PV silicon (Si) produced by cutting is also increased. Therefore, recycling PV Si produced by PV cutting is critical. Herein, we used PV Si to design a kind of boron-doped porous silicon/carbon (B-Si/C) composites through acid etching and freeze-drying methods. The B-Si/C has a uniform size (25–35 nm), rich pores and good dispersibility. Porous Si doped with B can shorten the ion transmission distance. Simultaneously, the outer carbon layer of B-Si/C can relieve the volume expansion of the Si nanoparticles and prevent the Si nanoparticles from agglomerating during charge–discharge cycles. When applied as anodes for lithium-ion batteries (LIBs), the B-Si/C exhibits superior electrochemical performance with a commendable capacity of 1240 mA h g−1 at 420 mA g−1 after 100 cycles. It is very viable environmentally and economically to produce advanced high-capacity anode materials for LIBs using PV Si.

Nitrogen‐doped reduced graphene oxide incorporated porous rod‐like cobalt molybdate as an anode for high‐capacity long‐life lithium‐ion batteries

Modification of volume expansion and poor conductivity of ternary metal molybdates as an anode for lithium-ion batteries (LIBs) results in the improvement of their reversibility and rate capability. Herein, porous rod-like cobalt molybdate incorporated with nitrogen (N) doped reduced graphene oxide (rGO) was fabricated using a silicone oil-bath method and further heated at 500°C (designated as CMO500@N-G) and 600°C (CMO600@N-G). The well-designed CMO500@N-G and CMO600@N-G electrodes were explored as an anode for LIBs. Notably, the CMO500@N-G electrode exhibited a discharge capacity of 612 mA h g−1 over 250 cycles at 100 mA g−1, while the CMO600@N-G was restricted to 199.5 mA h g−1. Besides, the CMO500@N-G electrode was sustained for 2000 cycles with a remarkable discharge capacity of 665 mA h g−1 even at a high current density of 1000 mA g−1. Finally, using a newly developed CMO500@N-G anode, a full cell LIB was also fabricated and showed good reversibility and excellent rate performance. This outstanding performance of the electrode can be ascribed to the unique rod-like morphology of cobalt molybdate with a highly conductive N doped rGO, which suggests a new strategy to fabricate high-capacity anode materials for LIBs.

Nitrogen-doped porous carbon microspheres for high-rate anode material in lithium-ion batteries

Developing high-capacity anode materials is urgent for next-generation lithium-ion batteries (LIBs) with the increasing need of larger scale applications. In order to obtain suitable anode materials, nitrogen-doped porous carbon microspheres (NPCMs) were prepared via spray drying followed by carbonization using chitosan as both carbon and nitrogen sources. The structure and properties of NPCMs were characterized by thermogravimetric, Raman spectroscopic, x-ray diffraction, scanning electron microscopic, transmission electron microscopic as well as x-ray photoelectron spectroscopic analysis, and the electrochemical performance of NPCM electrodes were also evaluated. The results show that the diameter of the obtained microspheres is 1–7 μm. When used as the anode material, the NPCMs display a reversible capacity of 443 mAh g−1 at 100 mA g−1 after 120 cycles and maintain a high capacity of 377 mAh g−1 at 1 A g−1 after 500 cycles. Even at a high current density of 4 A g−1, a discharge capacity of 256 mAh g−1 can also be obtained. The excellent rate performance and long cycle life of the electrode might be ascribed to the nitrogen-doping, porous and amorphous structure of NPCMs. The results suggest that the prepared NPCMs have the potential to be used as a promising anode material for high-capacity LIBs.

Synthesis and Electrochemical Performance of NiCO₂S₄ as Anode for Lithium-Ion Batteries.

NiCO2S4 with different morphology was controllably fabricated by a facile hydrothermal and solvothermal route. The as-obtained samples were analyzed and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The results reveal that the sample (NCS-1) prepared by hydrothermal method manifest a mixture of nanorods and nanospheres. The sample (NCS-2) synthesized by solvothermal process takes on spherical nanoparticles (NPs). It is found that the morphology of the sample has much influence on the electrochemical property. When applied as anode for lithium-ion batteries (LIBs), the NiCO2S4 NPs (NCS-2) possess the highest reversible discharge capacity of 1469.8 mAh g-1 compared with other two samples at the current density of 100 mA g-1 in the voltage window of 0.01-3 V. Additionally, it remains a specific capacity of 1163.7 mAh g-1 at a current density of 100 mAg-1 after 100 cycles. This excellent electrochemical performance arises from its unique mesoporous structure, which can reduce the transport lengths of both lithium ions and electrons. The mesoporous NiCO2S4 NPs show the great potential development of high-capacity anode materials for LIBs.

Novel spherical cobalt/nickel mixed-vanadates as high-capacity anodes in lithium ion batteries

In the past four years, transition metal vanadates have received booming attention as anode materials for lithium ion batteries (LIBs) due to their outstanding specific capacities, decent cycling performance and superior rate properties. Among them, Co3V2O8 is the most reported species. However the cobalt is expensive, thus the replacement of cobalt would be a favorable route. So far, mixed vanadates have been rarely reported because of the remarkable difficulty in fabrication, among which cobalt/nickel mixed vanadates are the most attractive. In this work, a facile and green hydrothermal method with organic linker has been developed, to achieve modulated cobalt/nickel mixtures. It was corroborated by the X-ray diffraction (XRD) patterns and cyclic voltammetry (CV) profiles that single phase of cubic Co3V2O8 crystal structures were formed. The mixed vanadates demonstrated ultrahigh reversible capacity of over ∼1800 mAh/g at the current density of 0.2 A/g after ∼200 cycles and superb rate capability of ∼600 mAh/g at 4 A/g. The enhanced electrochemical performances of the higher-nickel-ratio indicated their considerable potential as high-capacity anode materials in LIBs.

Superelastic air-bubbled graphene foam monoliths as structural buffer for compressible high-capacity anode materials in lithium-ion batteries

Superelastic porous graphene foam monoliths (GFMs) constraining high-capacity anode electrode materials of GeO2 nanoparticles (NPs) have been prepared by simple solution-processed approach and studied in lithium-ion batteries (LIBs). Through an optimization of GeO2 content in the composite as 40% by weight, the GeO2-NPs@GFM-2 anode shows a constant compressive stress of 14kPa at a high strain of 90% for 200 cycles and simultaneously features a high specific capacity of 900mAhg−1 for at least 350 cycles. Based on its excellent flexibility and electrochemical properties, a compressible LIB is fabricated as a proof-of-concept when the GeO2-NPs@GFM-2 is directly used as the binder-free anode and paired with a lithium metal. This compressive half cell is capable to deliver pressure-sensible power output under a range of compressive strains up to 90%, setting a new benchmark in area-specific capacity (5.76mAhcm−2) for compressible/flexible LIBs with an energy density of 224.7Whkg−1. Furthermore, we demonstrate the universality of this approach by replacing GeO2 with Si nanoparticles to prepare compressible Si-NPs@GFM anode materials with high capacity and stability, validating GFMs asa general and efficient structure buffer for high-capacity anode materials in LIBs.

Self-Limiting Lithiation in Silicon Nanowires

The rates of charging and discharging in lithium-ion batteries (LIBs) are critically controlled by the kinetics of Li insertion and extraction in solid-state electrodes. Silicon is being intensively studied as a high-capacity anode material for LIBs. However, the kinetics of Li reaction and diffusion in Si remain unclear. Here we report a combined experimental and theoretical study of the lithiation kinetics in individual Si nanowires. By using in situ transmission electron microscopy, we measure the rate of growth of a surface layer of amorphous Li(x)Si in crystalline Si nanowires during the first lithiation. The results show the self-limiting lithiation, which is attributed to the retardation effect of the lithiation-induced stress. Our work provides a direct measurement of the nanoscale growth kinetics in lithiated Si, and has implications on nanostructures for achieving the high capacity and high rate in the development of high performance LIBs.