Highly stable SiOx/multiwall carbon nanotube/N-doped carbon composite as anodes for lithium-ion batteries
Introduction
The rapid development of both electrical vehicles and large-scale energy storage systems has created great demands for lithium-ion batteries with high energy density and long cycle life [1]. Since the electrode materials play predominant part in deciding the energy density of lithium-ion batteries, developing high-capacity electrode materials has been pursued [2], [3]. Silicon is regarded as the most ideal anode material for lithium-ion batteries because of a high specific capacity of about 3600 mAh g−1 at room temperature, satisfying lithium insertion/extraction potentials and abundant resources [4]. However, the exceptional lithium-storage capability is accompanied by a huge volume variation upon cycling, which leads to structural instability of the electrode and becomes the biggest challenge for the application of Si-based materials [5], [6]. In recent two decades, although some important progress has been achieved, the large-scale application of silicon-based materials in lithium-ion batteries still faces many challenges [7], [8], [9], [10]. Especially when a high mass loading of active materials is used per unit area, it is still difficult to achieve stable cycle performance in prolonged cycling. Compared with pure silicon, silicon oxides not only have a relatively small volume change, but also Li2O and silicate salts formed during the initial lithiation severe as the dispersion and buffer media of silicon in subsequent cycles [11], [12], [13]. Overall, silicon oxide electrodes have better cyclic stability than the elemental silicon electrodes. Other than commercial SiO, nonstoichiometric SiOx (x>1) is synthesized readily by simple liquid phase chemical method, which is cost-effective and offers much more choices to improve its electrochemical performance. In the recent several years, SiOx has attracted the researchers’ attention and exhibits promising prospect [14], [15], [16], [17], [18], [19], [20]. For instance, Guo used cellulosic substances as template to prepare SiOx nanotubular materials [21]. The SiOx nanotube exhibited a reversible capacity of 940 mAh g−1 and the capacity retention kept over 91.5% after 50 cycles. SiOx/C composite synthesized by Zhao’ group via a template assisted hydrothermal route and a carbon-coating process demonstrated a specific capacity of 780 mA h g−1 with a 0.02% decay per cycle [20]. Lately, we fabricated graphene nanoplatelets-supported SiOx composite, which showed a stable reversible capacity of about 630 mAh g−1 and the capacity retention could be kept up to 250 cycles [22]. However, the cyclic stability of these materials is still far from the requirement of practical application and thus more advanced material structural design is needed. In this work, network-structural SiOx/MWCNT/N-doped C ternary composite is fabricated. Herein, MWCNT is used as the scaffold of anchoring SiOx. Because of high conductivity, excellent flexibility and large specific area [23], the introduction of MWCNT is expected to effectively improve the conductivity of the electrode and buffer the volume change of SiOx to a large extent. Considering the interface contact between SiOx/MWCNT particles is not good enough because of low conductive SiOx on the surface of MWCNT and the exposed SiOx nanoparticles tend to agglomeration during annealing and cycling, high conductive N-doped carbon is used to coat SiOx/MWCNT. The electrochemical measurement shows that such structural composite exhibits prominent cycle stability with a high reversible capacity.
Section snippets
Material preparation
A certain amount of MWCNT (US Research Nanomaterials, Inc.) was dispersed in a solution composed of 0.2 g of cetyltrimethylammonium bromide (CTAB), 25 mL of ethanol and 58 mL of distilled water via ultrasonication. Next, 2.5 mL of ammonium hydroxide was added and the solution was stirred at room temperature for 15 min. Subsequently, 1.8 mL of (C2H5O)3SiC2H5 was added dropwise to the above dispersion and stirring was continued until the solution completely became clear. The precipitate was collected
Results and discussion
The SiOx/MWCNT/N-doped C is synthesized by self-assembly, in situ polymerization reactions and physical coating, followed by heat treatment. Firstly, CTA+ cations were adsorbed on MWCNT surface by intermolecular interaction. With the help of aqueous ammonia, negatively charged oligomeric silicate species produced by the hydrolysis of (C2H5O)3SiC2H5 were adsorbed on the surface of CTA+-coated MWCNT by electrostatic interaction [24], [25]. The absorbed oligomeric alkyl silicate species
Conclusions
In summary, we successfully fabricate a network-structured SiOx/MWCNT/N-doped C anode composite for lithium-ion batteries. The SiOx/MWCNT/N-doped C composite exhibits excellent cyclic stability with a high capacity. After 450 deep charge–discharge cycles, the discharge capacity is still as high as 621 mAh g−1. The composite also demonstrates good rate capability. The excellent electrochemical performance of the SiOx/MWCNT/N-doped C should be attributed to the combination of MWCNT and N-doped
Acknowledgment
This research was financially supported by Natural Science Foundation of China (51374175 and 21576030), Lithium-ion Battery Innovative Team Project of China West Normal University (CXTD2015-1) and Foundation of enterprises, universities and research institutes of Jiangsu Province (BY2014037-31).
References (36)
- et al.
Impact analysis of vehicle-to-grid technology and charging strategies of electric vehicles on distribution networks—A review
J. Power Sources
(2015) - et al.
Nanostructured cathode materials for rechargeable lithium batteries
J. Power Sources
(2015) - et al.
Silicon-based materials as high capacity anodes for next generation lithium ion batteries
J. Power Sources
(2014) - et al.
Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells
J. Power Sources
(2007) - et al.
Electrochemical reduction of nano-SiO2 in hard carbon as anode material for lithium ion batteries
Electrochem. Commun.
(2008) - et al.
Highly efficient and scalable synthesis of SiOx/C composite with core-shell nanostructure as high-performance anode material for lithium ion batteries
Electrochim. Acta
(2015) - et al.
Nano-sized SiOx/C composite anode for lithium ion batteries
J. Power Sources
(2011) - et al.
Carbon-coated SiO2 nanoparticles as anode material for lithium ion batteries
J. Power Sources
(2011) - et al.
Electrochemical behaviors of nonstoichiometric silicon suboxides (SiOx) film prepared by reactive evaporation for lithium rechargeable batteries
J. Power Sources
(2013) - et al.
Microstructures and electrochemical performances of nano-sized SiOx (1.18 ≤ x ≤ 1.83) as an anode material for a lithium(Li)-ion battery
J. Power Sources
(2013)
Hollow nanotubular SiOx templated by cellulose fibers for lithium ion batteries
Electrochim. Acta
Fabrication of graphene nanoplatelets-supported SiOx-disordered carbon composite and its application in lithium-ion batteries
J. Power Sources
Fabrication and lithium storage performance of sugar apple-shaped SiOx@C nanocomposite spheres
J. Power Sources
Pore size determination in modified micro- and mesoporous materials. Pitfalls and limitations in gas adsorption data analysis
Micropor. Mesopor. Mat.
SiOx-C dual-phase glass for lithium ion battery anode with high capacity and stable cycling performance
J. Power Sources
Facile fabrication of 3D SiO2@graphene aerogel composites as anode material for lithium ion batteries
Electrochim. Acta
Hollow porous silicon oxide nanobelts for high-performance lithium storage
J. Power Sources
Electrochemical properties of LiFePO4-multiwalled carbon nanotubes composite cathode materials for lithium polymer battery
Electrochem. Commun.
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