Sodium lignosulphonate decomposing accumulated byproducts of quasi-solid aluminum-air batteries

Quasi-solid Al-air batteries with hydrogels are regarded as a promising power source because of their high specific capacity, small-scale bulk, high ionic conductivity and no leakage. However, increasing accumulations of byproducts on the interface between Al anode and solid-state electrolyte block discharging performance and lifespan of the batteries. Here, we firstly present a way of sodium lignosulphonate as a chelating agent for Al-air batteries, forming coordination compounds and decomposing discharging byproducts, where the coordination compounds can make aluminum ions transfer from anodic surface into the interior of hydrogel electrolyte. Compared to Al-air batteries without additive sodium lignosulphonate, the lifespan of the battery with sodium lignosulphonate can be prolonged by 124.6% at a current density of 1 mA cm −2 . Additionally, the battery can output high power density of 46.3 mW cm −2 at 56 mA cm −2 , and the maximum specific battery capacity of 2161.67 mA h g −1 is achieved at 20 mA cm −2 . The use of coordination compounds to decompose and migrate discharging byproducts is not only available for Al-air batteries but for other metal batteries. • The coordination compounds of Al ion and sodium lignosulphonate can be formed. • The accumulated byproduct between Al anode and hydrogel can be transferred. • The lifespan of the batteries was improved using sodium lignosulphonate.