scholarly journals One-step fabrication of nanosized LiFePO4/expanded graphite composites with a particle growth inhibitor and enhanced electrochemical performance of aqueous Li-ion capacitors

RSC Advances ◽  
2019 ◽  
Vol 9 (25) ◽  
pp. 14407-14416 ◽  
Author(s):  
Shixian Lv ◽  
Xugang Zhang ◽  
Pengxue Zhang ◽  
Junyu Xiang ◽  
Yawen Li ◽  
...  

It is reported that olivine-type lithium iron phosphate (LFP) for Li-ion batteries is one of the most widely utilized cathode materials, but its high-power applications are limited due to its intrinsically poor ion transfer rate and conductivity.

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 375 ◽  
Author(s):  
César Peralta P. ◽  
Giovani Vieira ◽  
Simon Meunier ◽  
Rodrigo Vale ◽  
Mauricio Salles ◽  
...  

Greenhouse gas emissions are one of the most critical worldwide concerns, and multiple efforts are being proposed to reduce these emissions. Shipping represents around 2% of global CO 2 emissions. Since ship power systems have a high dependence on fossil fuels, hybrid systems using diesel generators and batteries are becoming an interesting solution to reduce CO 2 emissions. In this article, we analyze the potential implementation of Li-ion batteries in a platform supply vessel system through simulations using HOMER software (Hybrid Optimization Model for Multiple Energy Resources). We evaluate the impact of battery characteristics such as round trip efficiency, rated power, and energy capacity. We also evaluate the potential CO 2 emissions reduction that could be achieved with two of the most common types of Li-ion batteries (lithium titanate, lithium iron phosphate). Furthermore, we consider that the Li-ion batteries are installed in a 20 ft container. Results indicate that the lithium iron phosphate battery has a better performance, even though the difference between both technologies is lower than 1% of total emissions. We also analyze the potential emissions reduction for different parts of a mission to an offshore platform for different configurations of the ship power system. The most significant potential CO 2 emissions reduction among the analyzed cases is 8.7% of the total emissions, and it is achieved by the configuration including the main and auxiliary diesel engines as well as batteries. Finally, we present managerial implications of these results for both companies operating ships and ship building companies.


RSC Advances ◽  
2017 ◽  
Vol 7 (53) ◽  
pp. 33544-33551 ◽  
Author(s):  
Ying Feng ◽  
Junjie Gu ◽  
Feng Yu ◽  
Chunfu Lin ◽  
Jinli Zhang ◽  
...  

This work first discloses the evolution of lattice parameters of the non-stoichiometric lithium iron phosphate crystals.


2017 ◽  
Vol 253 ◽  
pp. 389-397 ◽  
Author(s):  
Claude Karegeya ◽  
Abdelfattah Mahmoud ◽  
Bénédicte Vertruyen ◽  
Frédéric Hatert ◽  
Raphaël P. Hermann ◽  
...  

2019 ◽  
Author(s):  
Vasily D. Sumanov ◽  
Dmitry A. Aksyonov ◽  
Oleg A. Drozhzhin ◽  
Igor A. Presniakov ◽  
Alexey V. Sobolev ◽  
...  

Lithium iron phosphate LiFePO<sub>4</sub> triphylite is now one of the core positive electrode (cathode) materials enabling the Li-ion battery technology for stationary energy storage applications, which are important for broad implementation of the renewable energy sources. Despite the apparent simplicity of its crystal structure and chemical composition, LiFePO<sub>4</sub> is prone to off-stoichiometry and demonstrates rich defect chemistry owing to variations in the cation content and iron oxidation state, and to the redistribution of the cations and vacancies over two crystallographically distinct octahedral sites. The importance of the defects stems from their impact on the electrochemical performance, particularly on limiting the capacity and rate capability through blocking the Li ion diffusion along the channels of the olivine-type LiFePO<sub>4</sub> structure. Up to now the polyanionic (i.e. phosphate) sublattice has been considered idle on this playground. Here, we demonstrate that under hydrothermal conditions up to 16% of the phosphate groups can be replaced with hydroxyl groups yielding the Li<sub>1-x</sub>Fe<sub>1+x</sub>(PO<sub>4</sub>)<sub>1-y</sub>(OH)<sub>4y</sub> solid solutions, which we term “hydrotriphylites”. This substitution has tremendous effect on the chemical composition and crystal structure of the lithium iron phosphate causing abundant population of the Li-ion diffusion channels with the iron cations and off-center Li displacements due to their tighter bonding to oxygens. These perturbations trigger the formation of an acentric structure and increase the activation barriers for the Li-ion diffusion. The “hydrotriphylite”-type substitution also affects the magnetic properties by progressively lowering the Néel temperature. The off-stoichiometry caused by this substitution critically depends on the overall concentration of the precursors and reducing agent in the hydrothermal solutions, placing it among the most important parameters to control the chemical composition and defect concentration of the LiFePO<sub>4</sub>-based cathodes.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Patima Nizamidin ◽  
Abliz Yimit ◽  
Ismayil Nurulla ◽  
Kiminori Itoh

Yttrium-doped LiFePO4 powder was synthesized using the hydrothermal method in one step and was used as a sensing material. An optical waveguide (OWG) sensor based on Yttrium-doped LiFePO4 has been developed by spin coating a thin film of LiFe0.99Y0.01PO4 onto a single-mode Tin-diffused glass optical waveguide. Light was coupled into and out of glass OWG employed by a pair of prisms. The guided wave transmits in waveguide layer and passes through the film as an evanescent wave. The sensing film is stable in air, but when exposed to target gas at room temperature, its optical properties such as transmittance (T) and refractive index (nf) were changed; thus, the transmitted light intensity was changed. The LiFe0.99Y0.01PO4 thin film OWG exhibits reversible response to xylene gas in the range of 0.1–1000 ppm. When the concentration of BTX gases was lower than 1ppm, other substances caused a little interference with the detection of xylene vapor. Compared to pure LiFePO4 thin film OWG, this sensor exhibited higher sensitivity to BTXs.


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