High capacity positive electrodes for secondary Mg-ion batteries

Rasul, Shahid, Suzuki, Shinya, Yamaguchi, Shu and Miyayama, Masaru (2012) High capacity positive electrodes for secondary Mg-ion batteries. Electrochimica Acta, 82. pp. 243-249. ISSN 0013-4686

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Abstract

Composites of layered structured Birnessite–MnO2 and tunnel structured Hollandite–MnO2 in presence of acetylene black were synthesized as positive electrode materials for rechargeable Mg-ion batteries. Reversible insertion/extraction of Mg-ion in the host structures was examined in the potential range of −1.8 to 1.0 V vs. Ag/Ag+. Results indicated that Mg-ion exchanged Birnessite/acetylene black composite showed the highest discharge capacity (109 mAh g−1) at 1st discharge, when compared to other microstructures of Birnessite. Meanwhile, the composite comprising of 65 wt% Hol–MnO2 and 35 wt% acetylene black showed very high insertion of Mg-ion (0.87 Mg/Mn) corresponding to discharge capacity of 475 mAh g−1 when tested at 60 °C in galvanostatic mode. The layered and tunneled framework of the MnO2 was retained with minor displacive adjustments even after substantial Mg-ion insertion/extraction after several cycles. However, large specific capacity loss was observed after 20 cycles in all of the microstructures probably due to Mg-ion trapping in the host lattice. Furthermore, the effect of the cation (K+) present in the tunnel of Hollandite on Mg-ion diffusion was analyzed as well and it was concluded that tunnel cation could impede the movement of Mg-ion in host structure.

Item Type:	Article
Uncontrolled Keywords:	Mg-ion secondary batteries, Birnessite–MnO2, Hollandite–MnO2, Positive electrode, High energy density
Subjects:	H600 Electronic and Electrical Engineering
Department:	Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User:	Becky Skoyles
Date Deposited:	10 May 2019 12:00
Last Modified:	10 Oct 2019 19:15
URI:	http://nrl.northumbria.ac.uk/id/eprint/39254

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