Higher Capacity, Improved Conductive Matrix VB2/Air Batteries (Postprint)

Transition metal borides, such as VB2, have been investigated as alternative, higher capacity anode materials. The VB2 high capacity is due to the capability to undergo a 4060 mAh/g formula weight multiple electron (11 e -) alkaline oxidative discharge at a singular discharge potential plateau. With...

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Bibliographic Details
Main Authors: Lefler,Matthew, Stuart,Jessica, Licht,Stuart, Parkey,Jeff
Format: Report
Language:English
Subjects:
anode conductive matrix
anodes
coin cells
coulombic efficiency
energy density
metal air batteries
SANDWICH CONSTRUCTION
sbir (small business innovation research)
Transition metal borides
TRANSITION METALS
VB2/air batteries
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Summary:Transition metal borides, such as VB2, have been investigated as alternative, higher capacity anode materials. The VB2 high capacity is due to the capability to undergo a 4060 mAh/g formula weight multiple electron (11 e -) alkaline oxidative discharge at a singular discharge potential plateau. With a comparable formula weight (10 higher) to zinc, VB2 has an intrinsic gravimetric capacity five-fold higher than the 2 e - oxidation of the widely used zinc alkaline anode. One challenge to the implementation of VB2/air batteries is that resistive oxide products impede the discharge depth, and only thin anode batteries (for example 10 mAh in a 1 cm diameter cell) had been demonstrated to discharge effectively. This study demonstrates that (i) smaller particle size (nano-VB2, as opposed to macroscopic VB2) helps to alleviate this effect and (ii) a stacked anode compartment configurations improve the anode conductive matrix significantly, resulting in an increase in the coulombic efficiency of high capacity, thicker anodes in VB2/air batteries. Combined, these effects provide a 50% relative increase in the coulombic efficiency (from 50% to 75% at a 0.4 V discharge cutoff) of a 30 mAh coin cell, and increase the coulombic efficiency of the 100 mAh cell to 50%. Journal of The Electrochemical Society , 163, 5, 01 Jan 0001, 01 Jan 0001,