Studies On Modification And Behavior Of Actived Carbon Electrode Material For Ultra-battery

The ultra-battery is a hybrid energy-storage device， which takes the best fromlead-acid batteries and asymmetric super-capacitors. But because of the operationalpotentials mismatch between capacitor electrode and sponge lead negative plate, andsevere hydrogen evolution at the end of charging. To solve these problems,following studies have been done.In the experiment, first we investigated the physical and electrochemicalproperties of the activated carbon material. And then modify the carbon by chemicaldeposition，and researched the change of the electrode and material after themodification of the properties. Final we tested the asymmetric super-capacitors andultra-batteries used those material.A series of amounts of lead and bismuth and lead-bismuth compound have beendeposited into activate carbon. The BET, XRD, SEM, TEM and electrochemicalanalysis methods were tested on the material. The results showed that the presenceof the bismuth have the role of reducing the hydrogen evolution rate, and analyzinghydrogen evolution rate of modified carbon electrode at-1.4V, the modification ofbismuth at3/100have better effect of hydrogen evolution than others, but thedeposited of bismuth almost no effect of the operational potentials. With theincrease of deposited lead, hydrogen evolution rate of modified carbon graduallydecreased. Also analyzing hydrogen evolution rate of modified carbon electrode at-1.4V, it showed that more than30/100lead deposited into carbon, the hydrogenevolution rate decreased slowly, so the modified of lead at30/100is better. And thelead modified carbon material had a positive effect of the operational potential. Onthe basis, the result of the bismuth-lead compound modification show that thedeposited of bismuth and lead in the carbon at3/30/100, it can decrease thehydrogen evolution rate and improve the operational potential.Add the modified carbon materials of the3/100bismuth and30/100lead inlead-acid batteries composed super lead-acid batteries, SEM and on high-ratepartial-state-of-charge cycling’s results show that the batteries that containingdeposited of bismuth carbon have a longer life than lead-acid batteries, and1.5%carbon of bismuth have the longest cycle life. The comparison found that the batteryadd1.5%modifier of carbon’s end-of-charge lower than pure activate carbon,and1.5%carbon of bismuth have the longest cycle life. Above shows that themodification of the electrode can decrease the hydrogen evolution, and canimproved the cycle life.