A voltaic cell based on the reaction between aqueous Br2 and vanadium(III) ions has E°cell = 1.39 V:
Br2 (aq) + 2V3+ (aq) + 2H2O (l) 2VO2+ (aq) + 4H+ (aq) + 2Br- (aq)
What is E°vanadium, the standard electrode potential for the reduction of VO2+ to V3