Hidrogenação de ligas  à base de terras raras para fabricação de eletrodos negativos de baterias de níquel-hidreto metálico

Casini, Julio César Serafim

doi:10.11606/D.85.2011.tde-01062011-144128

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Master's Dissertation

DOI

https://doi.org/10.11606/D.85.2011.tde-01062011-144128

Document

Master's Dissertation

Author

Casini, Julio César Serafim (Catálogo USP)

Full name

Julio César Serafim Casini

E-mail

Institute/School/College

Instituto de Pesquisas Energéticas e Nucleares

Knowledge Area

Nuclear Technology Materials

Date of Defense

2011-04-08

Published

São Paulo, 2011

Supervisor

Takiishi, Hidetoshi (Catálogo USP)

Committee

Takiishi, Hidetoshi (President)
Oliveira Neto, Almir
Périgo, Elio Alberto

Title in Portuguese

Hidrogenação de ligas à base de terras raras para fabricação de eletrodos negativos de baterias de níquel-hidreto metálico

Keywords in Portuguese

baterias Ni-HM
hidrogenação
LaNi5
ligas de La-Mg-Ni
terras raras

Abstract in Portuguese

Neste trabalho foi estudado as ligas La0,7-xMgx Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (x = 0 a 0,7) como eletrodo negativo de baterias de níquel - hidreto metálico. A hidrogenação das ligas foi realizada com duas pressões de H2 (2 bar e 10 bar) e temperaturas (ambiente e 500°C). A capacidade de descarga das ba terias de níquel hidreto metálico foram analisadas pelo equipamento de testes elétricos ARBIN BT-4. As ligas, no estado bruto de fusão, foram analisadas por microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e difração de Raios-X. Com o aumento da concentração de Mg nas ligas aumenta-se a capacidade de descarga, porém nota-se a diminuição a estabilidade cíclica das baterias. A capacidade de descarga máxima obtida foi para a liga Mg0,7Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (60 mAh) e a bateria que apresentou a melhor performance foi La0,4Mg0,3Pr0,3Al0,3Mn0,4Co0,5Ni3,8 (53 mAh e 150 ciclos). A capacidade de absorção de hidrogênio diminui quando se adiciona Mg, não ocorrendo tal efeito para a liga Mg0,7Pr0,3Al0,3Mn0,4Co0,5Ni3,8.

Title in English

Hidrogenation of the rare earth alloys for production negative electrodes of nickel-metal hydride batteries

Keywords in English

hydrogenation
rare earth

Abstract in English

In this work were studied of La0.7-xMgx Pr0.3Al0.3Mn0.4Co0.5Ni3.8 (x = 0 and 0.7) alloys for negative electrodes of the nickel-metal hydride batteries. The hydrogenation of the alloys was performed varying pressing of H2 (2 and 10 bar) and temperature (room and 500°C). The discharge capacity of the nic kel-metal hydride batteries were analyzed in ARBIN BT- 4 electrical test equipment. The as-cast alloys were analyzed by scanning electron microscopy (SEM), energy disperse spectroscopy (EDX) and X-Ray diffraction. The increasing Mg addition in the alloy increases maximum discharge capacity but decrease cycle life of the batteries. The maximum discharge capacity was obtained with the Mg0.7Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy (60 mAh) and the battery which presented the best performance was La0.4Mg0.3Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy (53 mAh and 150 cycles). The H2 capability of absorption was diminished for increased Mg addition and no such effect occurs for Mg0.7Pr0.3Al0.3Mn0.4Co0.5Ni3.8 alloy.

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Publishing Date

2011-06-21

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