Higher Capacity, Improved Conductive Matrix VB2/Air Batteries (Postprint)
George Washington University Washington United States
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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 mAhg 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 VB2air 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 VB2air 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.