Preparation of four basic lead sulfate nano-rods additives and effect on the electrochemical performance of lead-acid battery

•A type of 4BS nano-rods is prepared by liquid phase suspension method.•The diameter of 4BS nano-rods can be controlled below 100 nm.•4BS nano-rods have high purity and electrochemical activity.•The positive active material with 4BS nano-rods has superior electrochemical performances.

As a type of commonly used active material additives, the grain size and structure of four basic lead sulfate (4BS) can seriously affect its performance. 4BS with smaller grain size and higher electrochemical activity can have a good additive effect. In this paper we prepare a type of 4BS nano-rods. By comparing the different sintering temperatures, it can be found that when the sintering is 400 °C, the 4BS can be prepared successfully and form nano-rod like crystal structure. The diameter can be controlled below 100 nm. CV and EIS results display that 4BS nano-rods has the higher electrochemical activity and active material conversion rate.When the 4BS nano-rods are added to the active material, large crystal structure is not present and stable active material skeleton can be formed. That can make it have the higher active material specific capacity and long cycle life. The charge and discharge results show that when the discharge current rate was 0.1 C, 0.25 C, 0.5 C and 1 C, the specific capacity of the positive active material with 4BS nano-rods can reach 80.71 mAh g−1, 75.67 mAh g−1, 67.70 mAh g−1 and 62.96 mAh g−1. With the increase of the current density, the specific capacity and the discharge voltage are not obviously decreased. After 100 cycles, the specific capacity was also only decreased by less than 20% of its initial capacity.