Synthesis of CeNb3O9 perovskite by Pechini method

Reis, Jussara V.; Pereira, Tayanna C.P.; Teles, Thamara H.A.; França, Alexandre Bôscaro; Bellido, Jorge David Alguiar; Naves, Fabiano Luiz; Baston, Eduardo Prado

doi:10.1016/j.matlet.2018.05.093

Cited by 11 publications

(4 citation statements)

References 13 publications

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“…The precursor material for the citric acid method was thermally characterized using TGA and DSC. Figure 3 displays the results where several stages of weight loss are seen which is typical of citric acid method (23). The peaks at 200C are excess ethylene glycol breaking down and releasing while the peaks at 400C are the polymeric chains decomposing, releasing the carbon and oxygen species.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Electrochemical Performance of a Homogenously Dispersed Li_aMn_1-x-y-ZFe_xCo_yNi_zO_2-DCl_d Lithium Ion Battery Cathode Material

2020

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Background: Lithium manganese oxide spinel is a strong candidate for lithium-ion battery cathodes due to its high operational voltage, three-dimensional network of lithium pathways within the structure, low toxicity, reasonable capacity, and low cost of raw materials. However, spinel suffers from diminished cycle life due to loss of crystallinity or fracturing of the structure either through the alternative phase formation or Jahn-Teller distortion. Historically, cycle life enhancements are achieved through stabilization of the spinel structure via transition metal doping on the B-site of the lattice; creating disorder necessary to stabilize the lattice structure during cycling. Previously, we have demonstrated a stabilization of this structure can also be achieved with a chlorine dopant on the oxygen site that results in enhanced performance at voltages below 3.0V when homogenously dispersed throughout the crystal, giving a desirable added capacity in a robust chemistry protected by this low voltage plateau. Single B-site dopants have been incorporated into these chlorinated spinels but rarely have several dopants been studied for optimizing and customizing cathode performance as well as anion dopant feasibility. Raw materials cost must be taken into to consideration when designing a novel cathode. An ideal cathode would limit scarce or unethically sourced materials like cobalt, and instead focus on considering inexpensive and available materials like iron. This effort focuses on the manganese substitution of up to three metals, iron, cobalt, and nickel, in order to stabilize the structure for further cycling while minimizing the need for cobalt incorporation. Several variations for LiaMn1-x-y-ZFexCoyNizO2-dCld will be presented that exhibit opportunities for 5.0+ V operation. Experimental: A wet chemical gel combustion method was used to synthesize metal-doped chlorinated lithium manganese oxide spinel. Stoichiometric amounts of Li(NO3), Mn(NO3)2∙4H2O, a metal-chloride salt appropriate for each metal, (Fe, Co, and/or Ni)(NO3)n, and a chelating agent (glycine or citric acid with ethylene glycol, Alfa Aesar/Sigma Aldrich) were dissolved into an aqueous or ethanol solution. The solution was heated to evaporate the water and form a gel, which was heated further to 250 °C when auto ignition occurs. The resultant ash was fired between 600 – 700°C for 2 to 12 hours to achieve the desired phase. Alternatively, an acetate-based synthesis is performed with metal acetate salts less a chlorine or lithium additive dissolved in distilled water. NH4OH is added to form a gel and is heated to evaporate the water. The gel is ignited above 200 °C and calcined at 400 °C in air. The resultant oxide is mixed with LiClO4 and LiOH and ground in solid state prior to a final calcination at 600 °C for 4 hours. Material characterization was performed using X-ray diffraction, X-ray fluorescence, thermogravimetric analysis, and scanning electron microscopy. Prepared active cathode materials were mixed with carbon black and polytetrafluoroethylene in a weight ratio of 85:10:5 of active to carbon to Teflon binder and calendared to 0.04 cm, punched into disks and pressed onto aluminum mesh opposite a Li metal anode. CR2025 button cells were filled with 1 M LiPF6 in a proportional mixture of diethyl carbonate, dimethyl carbonate, and ethylene carbonate. Electrochemical characterization was performed using electrochemical impedance spectroscopy (Solartron 1260) and cycling on an ARBIN MSTAT4 battery cycler system. Conclusion: Electrochemical data is presented for B-site dopants with two or more of the metals iron, cobalt and/or nickel. The results demonstrate an enhanced high voltage operation above 5.0 V coupled with a deep discharge capability below 3.0 V. In the case of LiaMn0.77Fe0.06Ni0.17O2-dCld, a cobalt-free cathode material exhibits a capacity of 210 mAh/g from 5.0V to 2.25V. An example electrochemical performance result is shown in the attached figure where LixMn0.945Fe0.05Co0.055O2-dCld is the active cathode material and lithium is the active anode material. For this example, the cell was cycled between 4.5 V and 3.5 V for the initial ten cycles. For the next three cycles, the cell was cycled between 5.25 V and 3.5 V. The next three cycles included a deep discharge between 5.25 V and 2.25 V before returning to cycling between 5.25 V and 3.5 V. The cycle plots indicate no loss of capacity when cycling between the aforementioned voltages. When discharging deep, there is a 50% increase in capacity and the return to high voltage charging without the deep discharge indicates the material is reversible and does not undergo permanent structural deformation. Importantly, a two-fold increase in capacity is shown when cycling to 4.5V (cycles 1-10) vs. 5.25V (cycles 11-13). Electrolytes with 5.0+ V stability will need to be studied further to enable the full potential of these presented cathodes. Figure 1

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Section: Resultsmentioning

confidence: 99%

Synthesis and Electrochemical Performance of a Homogenously Dispersed Li_aMn_1-x-y-ZFe_xCo_yNi_zO_2-DCl_d Lithium Ion Battery Cathode Material

2020

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“…As pesquisas [39][40][41][42] envolvendo o método Pechini utilizam água como solvente, no entanto, no presente estudo verificou-se que a utilização de álcool etílico foi mais eficiente, ocorrendo a cristalização da mulita, cuja amostra Etil apresentou uma cristalinidade de 51,6%, com formação de discretos picos de espinélio. Nesta reação, quando a quantidade de água foi diminuída, os íons de alumínio quelados pelo AC, que possuíam sítios reativos, reagiram com a sílica não mais segregada, formando a mulita.…”

Section: Resultsunclassified

Influência do tipo de solvente na síntese de mulita pelo método Pechini

et al. 2019

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Resumo Mulita é um aluminossilicato com grande importância na tecnologia cerâmica. Sua síntese através de métodos químicos tem sido extensivamente estudada, no entanto, não se observam estudos da sua obtenção pelo método Pechini. Assim, este estudo teve por objetivo a síntese de mulita por meio deste método. Foi avaliada a influência de diversos solventes na obtenção da mulita pela rota Pechini. As características dos pós foram avaliadas por difração de raios X, análise térmica (TG/DTG), adsorção de nitrogênio (BET), microscopia eletrônica de varredura e de transmissão. Os resultados obtidos comprovaram a eficiência do método Pechini, bem como a influência dos solventes na obtenção da fase, sendo a mulita obtida como fase majoritária e com maior cristalinidade quando do uso do álcool etílico como solvente.

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“…1) de lantânio, tiveram uma perda de massa de aproximadamente 34,4%, para a composição de praseodímio, essa perda foi cerca de 28,5% e para a composição de gadolínio, ocorreu aproximadamente 32% da perda de massa do material. A estabilidade para as três composições, ocorreu a partir de 730°C, no qual as curvas termogravimétricas dos três materiais, apresentaram eventos como: desidratação, relacionada a perda de água, e material volátil; e decomposição da matéria orgânica remanescente pela oxidação de quelatos metálicos (REIS et al, 2018).…”

Section: Resultsunclassified

Vivência E Práticas Agroecológicas: Um Relato De Experiência Em Assistência Técnica E Extensão Rural Em Municípios Do Recôncavo Baiano

Cavalcanti

Anjos

Silva

et al. 2019

Meio Ambiente, Sustentabilidade E Agroecologia 5

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Synthesis of CeNb3O9 perovskite by Pechini method

Cited by 11 publications

References 13 publications

Synthesis and Electrochemical Performance of a Homogenously Dispersed Li_aMn_1-x-y-ZFe_xCo_yNi_zO_2-DCl_d Lithium Ion Battery Cathode Material

Synthesis and Electrochemical Performance of a Homogenously Dispersed Li_aMn_1-x-y-ZFe_xCo_yNi_zO_2-DCl_d Lithium Ion Battery Cathode Material

Influência do tipo de solvente na síntese de mulita pelo método Pechini

Vivência E Práticas Agroecológicas: Um Relato De Experiência Em Assistência Técnica E Extensão Rural Em Municípios Do Recôncavo Baiano

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Synthesis of CeNb3O9 perovskite by Pechini method

Cited by 11 publications

References 13 publications

Synthesis and Electrochemical Performance of a Homogenously Dispersed LiaMn1-x-y-ZFexCoyNizO2-DCld Lithium Ion Battery Cathode Material

Synthesis and Electrochemical Performance of a Homogenously Dispersed LiaMn1-x-y-ZFexCoyNizO2-DCld Lithium Ion Battery Cathode Material

Influência do tipo de solvente na síntese de mulita pelo método Pechini

Vivência E Práticas Agroecológicas: Um Relato De Experiência Em Assistência Técnica E Extensão Rural Em Municípios Do Recôncavo Baiano

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Synthesis and Electrochemical Performance of a Homogenously Dispersed Li_aMn_1-x-y-ZFe_xCo_yNi_zO_2-DCl_d Lithium Ion Battery Cathode Material

Synthesis and Electrochemical Performance of a Homogenously Dispersed Li_aMn_1-x-y-ZFe_xCo_yNi_zO_2-DCl_d Lithium Ion Battery Cathode Material