scholarly journals Effect of Reducing Agent on Solution Synthesis of Li3V2(PO4)3 Cathode Material for Lithium Ion Batteries

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3746 ◽  
Author(s):  
Ali Yaghtin ◽  
Seyyed Morteza Masoudpanah ◽  
Masood Hasheminiasari ◽  
Amirhossein Salehi ◽  
Dorsasadat Safanama ◽  
...  

In this study, Li3V2(PO4)3 (LVP) powders are prepared by a solution synthesis method. The effects of two reducing agents on crystal structure and morphology and electrochemical properties are investigated. Preliminary studies on reducing agents such as oxalic acid and citric acid, are used to reduce the vanadium (V) precursor. The oxalic acid-assisted synthesis induces smaller particles (30 nm) compared with the citric acid-assisted synthesis (70 nm). The LVP powders obtained by the oxalic acid exhibit a higher specific capacity (124 mAh g−1 at 1C) and better cycling performance (122 mAh g−1 following 50 cycles at 1C rate) than those for the citric acid. This is due to their higher electronic conductivity caused by carbon coating and downsizing the particles. The charge-discharge plateaus obtained from cyclic voltammetry are in good agreement with galvanostatic cycling profiles.

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1732
Author(s):  
Dan Zhao ◽  
Qian Zhao ◽  
Zhenyu Wang ◽  
Lan Feng ◽  
Jinying Zhang ◽  
...  

Potassium-ion batteries (KIBs) have come up as a potential alternative to lithium-ion batteries due to abundant potassium storage in the crust. Red phosphorus is a promising anode material for KIBs with abundant resources and high theoretical capacity. Nevertheless, large volume expansion, low electronic conductivity, and limited K+ charging speed in red phosphorus upon cycling have severely hindered the development of red phosphorus-based anodes. To obtain improved conductivity and structural stability, surface engineering of red phosphorus is required. Poly(3,4-ethylenedioxythiophene) (PEDOT)-coated red phosphorus nanospheres (RPNP@PEDOT) with an average diameter of 60 nm were synthesized via a facile solution-phase approach. PEDOT can relieve the volume change of red phosphorus and promote electron/ion transportation during charge−discharge cycles, which is partially corroborated by our DFT calculations. A specific capacity of 402 mAh g−1 at 0.1 A g−1 after 40 cycles, and a specific capacity of 302 mAh g−1 at 0.5 A g−1 after 275 cycles, were achieved by RPNP@PEDOT anode with a high pseudocapacitive contribution of 62%. The surface–interface engineering for the organic–inorganic composite of RPNP@PEDOT provides a novel perspective for broad applications of red phosphorus-based KIBs in fast charging occasions.


2015 ◽  
Vol 39 (2) ◽  
pp. 1094-1100 ◽  
Author(s):  
Muchun Liu ◽  
Yan Zhao ◽  
Sen Gao ◽  
Yan Wang ◽  
Yuexin Duan ◽  
...  

Microwave-assisted solution treatment provides a simple and safe synthesis for nanomaterials and nanocomposites. LiFePO4–graphene–C nanoplatelets show excellent cycling performance.


2021 ◽  
Author(s):  
Wencai Zhao ◽  
Y.F. Yuan ◽  
S.M. Yin ◽  
Gaoshen Cai ◽  
S.Y. Guo

Abstract Hollow mesoporous nanospheres MoO2/C are successfully constructed through metal chelating reaction between molybdenum acetylacetone and glycerol as well as the Kirkendall effect induced by diammonium hydrogen phosphate. MoO2 nanoparticles coupled by amorphous carbon are assembled to unique zigzag-like hollow mesoporous nanosphere with large specific surface area of 147.7 m2 g-1 and main pore size of 8.7 nm. The content of carbon is 9.1%. As anode material for lithium-ion batteries, the composite shows high specific capacity and excellent cycling performance. At 0.2 A g-1, average discharge capacity stabilizes at 1092 mAh g-1. At 1 A g-1 after 700 cycles, the discharge capacity still reaches 512 mAh g-1. Impressively, the composite preserves intact after 700 cycles. Even at 5 A g-1, the discharge capacity can reach 321 mAh g-1, exhibiting superior rate capability. Various kinetics analyses demonstrate that in electrochemical reaction, the proportion of the surface capacitive effect is higher, and the composite has relatively high diffusion coefficient of Li ions and fast faradic reaction kinetics. Excellent lithium storge performance is attributed to the synergistic effect of zigzag-like hollow mesoporous nanosphere and amorphous carbon, which improves reaction kinetics, structure stability and electronic conductivity of MoO2. The present work provides a new useful structure design strategy for advanced energy storage application of MoO2.


2020 ◽  
Vol 860 ◽  
pp. 69-74
Author(s):  
Iman Rahayu ◽  
Engela Evy Ernawati ◽  
Atiek Rostika Noviyanti ◽  
Yusra Linda ◽  
Diana Rakhmawaty ◽  
...  

In the recent years, LiFePO4 has been widely developed as a cathode for lithium ion batteries because it has high theoretical capacity (170 mAh/g), good stability and is also environmentally friendly. However, the poor electronic conductivity (~10-9 S/cm) and low diffusion coefficient of lithium ion (~10-15-10-14 cm2/s) are limiting its application. Some solutions to overcome this problem are carbon coating and doping metal ions. This study aims to determine the effect of Gd3+ ion doping on the electronic conductivity of LiFePO4/C. The synthesis method was used is carbothermal reduction with Fe2O3, Gd2O3, LiH2PO4 and carbon black reagents. The synthesized LiFe1-xGdxPO4/C was characterized using XRD, SEM-EDS, and four point probes. The results obtained showed that gadolinium ion doping increased the conductivity of LiFePO4/C from 1.8952 x10-6 to 8.69x10-6 Scm-1 using 0.07 mol ion Gd3+.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Haipeng Li ◽  
Shuang Yang ◽  
Yan Zhao ◽  
Taizhe Tan ◽  
Xin Wang ◽  
...  

ZnO has attracted considerable attention as electrode material in lithium-ion battery (LIB) due to its theoretically high capacity. However, poor electronic conductivity and huge volumetric changes during cycling limit its industrial applications. In this work, polypyrrole nanorings (PNRs) were successfully prepared via the solution chemistry method using pyrrole (Py) as raw material, ammonium persulfate (APS) as oxidant, and cetyltrimethyl ammonium bromide (CTAB) as surfactant. The ZnO/PNR composite was synthesized with zinc oxide nanoparticles absorbed on the surface of PPy nanorings through the one-pot in situ sol-gel method. The composite shows a three-dimensional intertwined network structure where the size of polypyrrole nanorings ranges from 80 nm to 100 nm in diameter and the average size of uniformly distributed ZnO nanocrystals is 10.49 nm. The unique three-dimensional conductive framework can provide good electronic contact between the ZnO particles and buffer the volume variation during the lithiation/delithiation processes. As an electrode material for LIBs, the ZnO/PNR composite delivers a first cycle discharge capacity of 1658 mAh g-1 and a capacity retention of 50.7% over 150 cycles at 200 mA g-1, indicating high specific capacity and outstanding cycle stability.


RSC Advances ◽  
2014 ◽  
Vol 4 (78) ◽  
pp. 41281-41286 ◽  
Author(s):  
Wenjuan Jiang ◽  
Weiyao Zeng ◽  
Zengsheng Ma ◽  
Yong Pan ◽  
Jianguo Lin ◽  
...  

Good electronic conductivity and mechanical properties are obtained by introducing CNTs into an ANSO@CNTs anode material. The anode possesses a super cycling performance and a high rate capability because the porous structure facilitates liquid electrolyte diffusion into active materials.


2011 ◽  
Vol 391-392 ◽  
pp. 377-380
Author(s):  
Guo Jun Li ◽  
Ming Yang ◽  
Hai Li Jing ◽  
Rui Ming Ren

LiFePO4/C composite powders were prepared by a simple reaction of as-synthesized FePO4•2H2O, LiOH•H2O, oxalic acid and citric acid. The influence of oxalic acid and citric acid in different ratios was investigated on morphology and electrochemical performance of LiFePO4/C composite powders. The characterization of the composites included X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis indicates that the material is well crystallized without impurities. The obtained LiFePO4/C composite powders with well dispersion at CA/OA ratio of 1:1.50 and the initial charge capacity reached 159.3 mAhg-1 at 0.1C rate, meanwhile, the particles prepared at 1:0.75 were close to spherical in shape and the specific capacity value was 149.8 mAhg-1 at 0.1C rate, with a slight decrease on greater C-rates reaching 141.3 mAhg-1 at 1C.


2020 ◽  
Vol 20 (11) ◽  
pp. 7051-7056
Author(s):  
Jungwon Heo ◽  
Anupriya K. Haridas ◽  
Xueying Li ◽  
Rakesh Saroha ◽  
Younki Lee ◽  
...  

Transition metal oxide materials with high theoretical capacities have been studied as substitutes for commercial graphite in lithiumion batteries. Among these, SnO2 is a promising alloying reaction-based anode material. However, the problem of rapid capacity fading in SnO2 due to volume variation during the alloying/dealloying processes must be solved. The lithiation of SnO2 results in the formation of a Li2O matrix. Herein, the volume variation of SnO2 was suppressed by controlling the voltage window to 1 V to prevent the delithiation reaction between Li2O and Sn. Using this strategy the unreacted Li2O matrix was enriched with metallic Sn particles, thereby providing a pathway for lithium ions. The specific capacity decay in the voltage window of 0.05–3 V was 1.8% per cycle. However, the specific capacity decay was improved to 0.04% per cycle after the voltage window was restricted (in the range of 0.05–1 V). This strategy resulted in a specific capacity of 374.7 mAh g−1 at 0.1 C after 40 cycles for the SnO2 anode.


2021 ◽  
Vol 11 (24) ◽  
pp. 11713
Author(s):  
Marcella Bini ◽  
Marco Ambrosetti ◽  
Daniele Spada

Ferrites, a broad class of ceramic oxides, possess intriguing physico-chemical properties, mainly due to their unique structural features, that, during these last 50–60 years, made them the materials of choice for many different applications. They are, indeed, applied as inductors, high-frequency materials, for electric field suppression, as catalysts and sensors, in nanomedicine for magneto-fluid hyperthermia and magnetic resonance imaging, and, more recently, in electrochemistry. In particular, ZnFe2O4 and its solid solutions are drawing scientists’ attention for the application as anode materials for lithium-ion batteries (LIBs). The main reasons are found in the low cost, abundance, and environmental friendliness of both Zn and Fe precursors, high surface-to-volume ratio, relatively short path for Li-ion diffusion, low working voltage of about 1.5 V for lithium extraction, and the high theoretical specific capacity (1072 mA h g−1). However, some drawbacks are represented by fast capacity fading and poor rate capability, resulting from a low electronic conductivity, severe agglomeration, and large volume change during lithiation/delithiation processes. In this review, the main synthesis methods of spinels will be briefly discussed before presenting the most recent and promising electrochemical results on ZnFe2O4 obtained with peculiar morphologies/architectures or as composites, which represent the focus of this review.


2019 ◽  
Author(s):  
Panpan Wang ◽  
Yue Du ◽  
Baoyou Zhang ◽  
Yanxin Yao ◽  
Yuchen Xiao ◽  
...  

The <i>β-</i>phase lithium vanadium oxide bronze (<i>β-</i>Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub>) with high theoretic specific capacity up to 440 mAh g<sup>-1</sup> is considered as promising cathode materials, however, their practical application is hindered by its poor ionic and electronic conductivity, resulting in unsatisfied cyclic stability and rate capability. Herein, we report the surface decoration of <i>β-</i>Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub> cathode using both reduced oxide graphene and ionic conductor LaPO<sub>4</sub>, which significantly promotes the electronic transfer and Li<sup>+</sup> diffusion rate, respectively. As a result, the rGO/LaPO<sub>4</sub>/Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub> composite exhibits excellent electrochemical performance in terms of high reversible specific capacity of 275.7 mAh g<sup>-1</sup> with high capacity retention of 84.1% after 100 cycles at a current density of 60 mA g<sup>-1</sup>, and acceptable specific capacity of 170.3 mAh g<sup>-1</sup> at high current density of 400 mA g<sup>-1</sup>. The cycled electrode is also analyzed by electrochemical impedance spectroscopy, <i>ex-situ </i>X-ray diffraction and scanning electron microscope, providing further insights into the improvement of electrochemical performance. Our results provide an effective approach to boost the electrochemical properties of lithium vanadates for practical application in lithium ion batteries.


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