ELECTROCHIMICA ACTA
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2018
·
IF 5.116
Zhengyi Qian,Baoyu Sun,Lei Du,Shuaifeng Lou,Chunyu Du,Pengjian Zuo,Yulin Ma,Xinqun Cheng,YunZhi Gao,Geping Yin
Since electrode surfaces primarily house the sites of oxygen reduction/evolution reactions, surface chemistry is pivotal for both charge and discharge processes of Li–O 2 batteries . Herein, we introduce oxygen-containing functional groups associated with defects on the carbon fiber papers (functionalization) via acid treatment and investigate their effects on the rechargeable nonaqueous Li–O 2 batteries. The discharge platform increases from 2.68 V to 2.79 V, meanwhile the decreased charge overpotential (a drop of 0.84 V) is also observed after functionalization. It is found that the discharge products formed on pristine carbon fiber exhibit a huge toroidal-like structure, in contrast to the porous flake clusters with much smaller size on the functionalized carbon fiber. On the other hand, the smaller product clusters are found to be much easier to be oxidized, leading to remarkably reduced charge overpotential. In this regard, the decomposition of electrolyte and corrosion of carbon cathode are dramatically alleviated, thus leading to greatly promoted cycling performance. All the experimental facts suggest that the oxygen functional groups associated with defects could provide tremendous active sites for the nucleation of discharge products and result in remarkably decreased overpotential for both the oxygen reduction and the oxygen evolution reaction in our cases.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2018
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IF 2.88
Dongfei Li,Naicui Zhai,Shichong Xu,Mingzhe Zhang,Chenglin Sun,Haibo Li
Raman spectra of the solution of LiClO 4 in acetonitrile (CH 3 CN) at different concentrations have been measured. With increasing the concentration of Li + , it was noted that several vibrational modes of CH 3 CN had significant changes in Raman shifts and some new Raman peaks emerged due to the CH 3 CN⋯Li + complex formation. In addition, Fermi resonance phenomenon between the ν 2 ' and ( ν 3 + ν 4 ) ' Raman bands of CH 3 CN⋯Li + complex was observed. Based on the Bertran's equations, Fermi resonance parameters of free CH 3 CN and CH 3 CN⋯Li + complex at different concentrations have been calculated, respectively. Compared the Fermi resonance coupling coefficients W of free CH 3 CN with CH 3 CN⋯Li + complex at different concentrations, the free CH 3 CN had a little smaller value, which indicated that the ν 2 ' /( ν 3 + ν 4 ) ' Fermi resonance in CH 3 CN⋯Li + complex was much stronger than the ν 2 / ν 3 + ν 4 Fermi resonance in CH 3 CN. From the detailed analysis of the effect of Li + on the spectral features of CH 3 CN, the effect mechanism of Li + coordination to CH 3 CN at the nitrogen of the CN group on the ν 2 / ν 3 + ν 4 Fermi resonance of CH 3 CN has been elucidated.
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ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Yuebin Yang,Hui Xu,Shanxing Wang,Yuanfu Deng,Xianying Qin,Xusong Qin,Guohua Chen
Li-ion batteries have held a dominant position in the energy storage area for decades. However, due to the limitation of its chemistry , the energy density of Li-ion batteries is limited to ∼300 W h kg −1 . In recent years, more attention has been paid to the Li-S batteries that are environmentally friendly, cost-effective and high energy density (theoretical value of cathode: ∼2600 W h kg −1 ). In this study, carbonized polydopamine (C-PDA)-coated hollow carbon nanofibers (CNFs) with TiO 2 nanoparticles interspersed in the void space between the CNF skeleton and carbon coating layer were subtly designed. The C-PDA/TiO 2 /CNF composite (CTC) was integrated with the commercial separator as a polysulfide filter to achieve high-performance Li-S batteries. It is reveals that the CTC coating layer could effectively filter and reactivate the dissolved polysulfides to achieve a stabilized sulfur-based cathode. The Li-S battery assembled by this integrated separator and the regular cathode (sulfur/Ketjen black) with 72.7 wt% of sulfur achieved a high specific capacity and low decay rate (632.5 mAh g −1 at the first cycle and 0.06% per cycle) at 2.0C for 500 cycles. These good results indicate that the C-PDA/TiO 2 /CNF-modified separator could be a promising separator candidate for high performance Li-S batteries.
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JOURNAL OF POWER SOURCES
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2018
·
IF 6.945
Jingyi Wu,Hongxia Zeng,Qingxuan Shi,Xiongwei Li,Qing Xia,Zhigang Xue,Yunsheng Ye,Xiaolin Xie
Uncontrollable lithium (Li) dendrite growth has hampered the application of lithium metal batteries (LMBs). Herein, a novel plastic crystal composite polymer electrolyte (nh-CPE) consisting of multifunctional two-dimensional (2D) molybdenum disulfide (MoS 2 ) and ion-conducting one-dimensional (1D) surfactant oxidized cellulose nanocrystal (OCNC) is developed to overcome this challenge. The nh-CPE possesses good Li-dendrite-suppressing ability, which is attributed to the well-designed three-dimensional (3D) ion conducting network constructed by homogeneously dispersed MoS 2 and OCNC. This structure facilitates Li-ion conductivity and enables uniform Li deposition on the anode. Moreover, the impermeable MoS 2 nano-flakes with excellent mechanical strength serve as physical barriers to hold the electrolyte-electrode interface stability and consequently block Li dendrite growth and enhance fire retardancy. When applied in LMB, the nh-CPE exhibits excellent cycle performance and rate capability, with 90% capacity retention after 200 cycles at 0.5 C and 60 °C, and a discharge capacity of 128 mAh g −1 at 1 C. Notably, owing to high room-temperature ionic conductivity (0.8 mS cm −1 ), the cell with nh-CPE cycled at room temperature delivers an initial discharge capacity of 144 mAh g −1 . The outstanding performance and simple process offer great opportunity to promote Li-dendrite-suppressing LMBs for practical application.
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CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Fanyu Kong,Xiaodong He,Qianqian Liu,Xinxin Qi,Yongting Zheng,Rongguo Wang,Yuelei Bai
The presented work compared the etching behavior between combustion synthesized Ti 3 AlC 2 (SHS-Ti 3 AlC 2 ) and pressureless synthesized Ti 3 AlC 2 (PLS-Ti 3 AlC 2 ). Because the former had a more compact structure, it was harder to be etched than PLS-Ti 3 AlC 2 under the same conditions. When served as anode material for Li-ion batteries, SHS-Ti 3 C 2 showed much lower capacity than PLS-Ti 3 C 2 at 1 C (52.7 and 87.4 mAh g −1 , respectively) due to the smaller d -spacing. Furthermore, Potentiostatic Intermittent Titration Technique (PITT) was used to determine the Li-ion chemical diffusion coefficient ( D Li + ) of Ti 3 C 2 in the range of 10 −10 − 10 −9 cm 2 s −1 , indicating that Ti 3 C 2 could exhibit an excellent diffusion mobility for Li-ion.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2014
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IF 2.726
Mingye Ding,Yaru Ni,Yan Song,Xiaoxia Liu,Tengli Cui,Daqin Chen,Zhenguo Ji,Feng Xu,Chunhua Lu,Zhongzi Xu
Currently, enhancing luminescence efficiency of upconversion nanoparticles (UCNPs) has still been a challenging topic in despite of many efforts to improve UC luminescence. In this paper, a new strategy to enhance UC emission has been described based on coupling of Li + ions doping with growth an inert shell. Significant enhancement of upconversion (UC) luminescence intensity of lanthanide-doped nanoparticles was observed under synergistic effect of internal adjustment and external approach. In addition, the mechanism for the luminescence enhancement of UCNPs has been discussed. Our results suggest that this UC enhancement strategy, proven here in NaGdF 4 nanoparticles, could be extended to other lanthanide-doped nanocrystal systems for applications ranging from luminescent biological labels to volumetric three-dimensional displays.
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CHINESE CHEMICAL LETTERS
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2014
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IF 1.178
Wei Wei,Ling-Xiao Song,Lin Guo
SnO 2 hollow nanospheres were successfully synthesized via a facile one-step solvothermal method. Characterizations show that the as-prepared SnO 2 spheres are of hollow structure with a diameter at around 50 nm, and especially, the shell of the spheres is assembled by single layer SnO 2 nanocrystals. The surface area of the material reaches up to 202.5 m 2 /g. As an anode material for Li ion batteries, the sample exhibited improved electrochemical performance compared with commercial SnO 2 particles. After cycled at high current rate of 0.5 C, 1 C and 0.5 C for 20 cycles, respectively, the electrode can maintain a capacity of 509 mAh/g. The suitable shell thickness/diameter ratio endows the good structural stability of the material during cycling, which promises the excellent cycling performance of the electrode. The large surface area and the ultra thin shell ensure the high rate performance of the material.
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Nanoscale
·
2015
·Vol. 7
·期 33
·13840-13847
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IF 7.394
Lei Wang,Biao Gao,Changjian Peng,Xiang Peng,Jijiang Fu,Paul K. Chu,Kaifu Huo
Silicon-based nanomaterials are promising anode materials in lithium-ion batteries (LIBs) due to their high theoretical capacity of 4200 mA h g−1, more than 10 times that of commercial graphite. Si nanoparticles (NPs) with a diameter of or below 10 nm generally exhibit enhanced lithium storage properties due to their small size and large surface area. However, it is challenging to generate such ultrafine Si NPs by a facile and scalable method. This paper reports a scalable method to fabricate ultrafine Si NPs 5–8 nm in size from dead bamboo leaves (BLs) by thermally decomposing the organic matter, followed by magnesiothermic reduction in the presence of NaCl as a heat scavenger. The ultrafine Si NPs show a high capacity of 1800 mA h g−1 at a 0.2 C (1 C = 4200 mA g−1) rate and are thus promising anode materials in lithium-ion batteries. To achieve better rate capability, the BLs-derived ultrafine Si NPs are coated with a thin amorphous carbon layer (Si@C) and then dispersed and embedded in a reduced graphene oxide (RGO) network to produce Si@C/RGO nanocomposites by a layer-by-layer assembly method. The double protection rendered by the carbon shell and RGO network synergistically yield structural stability, high electrical conductivity and a stable solid electrolyte interface during Li insertion/extraction. The Si@C/RGO nanocomposites show excellent battery properties with a high capacity of 1400 mA h g−1 at a high current density of 2 C and remarkable rate performance with a capacity retention of 60% when the current density is increased 20 times from 0.2 to 4 C. This work provides a simple, low cost, and scalable approach enabling the use of BL waste as a sustainable source for the production of ultrafine Si NPs towards high-performance LIBs.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2015
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IF 2.729
Qijiu Deng,Jing Xue,Wei Zou,Liping Wang,Aijun Zhou,Jingze Li
A functional organic small molecule anode material (dilithium 2,5-dihydroxyterephthalate, Li 2 DHTP) is synthesized via a simple wet chemistry methodology adopting 2,5-dihydroxyterephthalic acid (DHTPA) as the precursor. It delivers a high specific capacity of 165 mAh/g over 100 cycles with the coulombic efficiency of 98% and shows remarkable rate performance. The organic acid DHTPA also demonstrates electrochemical activity toward Li + storage and releases but with poor cyclic performance. XRD and FT-IR studies suggest that the de −/lithiation process of chemically replaced Li 2 DHTP is highly reversible. On the contrary, the de −/lithiation process of electrochemically replaced Li 2 DHTP intermediate product, where the corresponding DHTPA acid experiences an ion exchange process in the first discharge process, shows quite poor reversibility in the following cycles. The results illustrate that either chemical replacement or electrochemical replacement of DHTPA can generate Li 2 DHTP electrochemical active material. This methodology might be applied to synthesize advanced organic small molecules conjugated carbonyl materials for energy storage.
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MATERIALS CHEMISTRY AND PHYSICS
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2016
·
IF 2.101
Liyan Zhou,Shancheng Yan,Zixia Lin,Yi Shi
Two-dimensional transition-metal dichalcogenides, such as tungsten disulfide (WS 2 ), have been actively studied as suitable candidates for anode materials used in lithium ion batteries recently, due to their remarkable ion intercalation properties. However, the difficulties in the synthesis of phase-pure WS 2 , restacking between WS 2 nanosheets, low electronic conductivity and brittle nature of WS 2 severely limit its Li-ion batteries application. Here, we adopt a one-pot method for synthesizing of WS 2 /reduced Graphene Oxide (rGO) composite to improve the battery performance dramatically. The WS 2 /rGO anode shows a stable discharge capacity of 431.2 mAh/g, at a current density of 0.1 A/g after 100 cycles, while the capacity of bare WS 2 is only 65.5 mAh/g under the same condition. The added graphene oxide is reduced to rGO in reaction process and constitute stable composite with WS 2 , not only avoiding the restacking between WS 2 nanosheets and improving the conductive properties, but also promoting the reduction of WO 3 effectively. Our work may provide a possible route to avoid oxygen impurities in transition metal dichalcogenides .
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Materials Research-Ibero-american Journal of Materials
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2017
·Vol. 20
·期 3
·592-600
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IF 0.634
Wen Yong,Pei Li-zhai,Wei Tian
Li doped bismuth oxide nanorods have been prepared using sodium bismuthate and Li acetate. X-ray diffraction (XRD) pattern shows that the nanorods are composed of monoclinic Bi2O4 and cubic LiBi12O18.50 phases. Scanning electron microscopy (SEM) observation shows that the nanorods have the length and diameter of 1-5 µm and 50-350 nm, respectively. The formation of the Li doped bismuth oxide nanorods is closely relative to the hydrothermal conditions. The electrochemical performance for the determination of L-cysteine based on a Li doped bismuth oxide nanorods modified glassy carbon electrode (GCE) has been developed. The CV peak current increases obviously and linearly with increasing the scan rate. Under the optimal conditions, Li doped bismuth oxide nanorods modified GCE exhibits good analytical performance with good reproducibility and stability. The linear range of L-cysteine is 0.0001-2 mM and the detection limit is 0.36 µM and 0.17 µM for cvp1 and cvp2, respectively.
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JOURNAL OF MEMBRANE SCIENCE
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2017
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IF 6.035
Guoping Chen,Xiong Song,Suqing Wang,Ying Wang,Tuo Gao,Liang-Xin Ding,Haihui Wang
Lithium–sulfur (Li–S) battery is considered as one of the most promising advanced energy storage devices. However, several critical issues remain which restrict their practical applications, especially the shuttle effect of soluble lithium polysulfides . Herein, we designed a lightweight multifunctional layer comprising reduced graphene oxide (rGO) and cobalt/nitrogen co-doped carbon nanofibers (Co-N-C) to modified the polypropylene (PP) separator to facilitate the electrochemical performance of Li–S batteries. The Co-N-C/rGO layer with abundant mesopores possesses strong immobilization ability of polysulfides and high electronic conductivity, which could work as an intrinsic physical/chemical frame work barrier and an upper current collector to trap and reutilize the polysulfides. Consequently, the Li–S battery with the modified Co-N-C/rGO/PP separator exhibits excellent cycling performance and good rate capability. A high discharge capacity of 1344 mAh g –1 at 0.1 C, 658 mAh g –1 at 5 C and a low capacity degradation rate of 28.8% after 500 cycles at 0.5 C were obtained. These exciting results indicate that this multifunctional Co-N-C/rGO/PP separator could be a promising separator candidate for Li–S batteries.
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