碱性溶液中,VB2和TiB2分别发生了 11电子和 6电子氧化反应,释放出 3 100mAh/g和 1 600mAh/g的超常电化学容量.对此,初步的解释是:在二硼化物中过渡金属与硼的电子转移使硼元素电负性增强,引起硼的电化学活化.使得合金的电极电势钳制在较负区域,导致某些过渡金属元素处于活化态,进而发生电化学氧化释放出电化学能量.
The transition metal borides VB_2 and TiB_2 were tested as high capacity anode materials and their electrochemical behaviors were studied by cyclic voltammetry and discharge measurements. The experimental results indicated that transition metal borides VB_2 and TiB_2 electrodes can deliver exceptionally high discharge capacity of over 3100 mAH/g and 1 600 mAH/g respectively, corresponding to 11- and 6-electron oxidation reaction, although their parent elements V, Ti and boron, are almost completely electrochemically inert. The different electrochemical activitis were probably due to the electrochemical activation of boron, which clamp the potential to passivation for Ti and activity for V.
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