Rapid treatment of LLZTO solid electrolyte surface impurities by lactic acid solution

LLZO solid-state electrolytes of the garnet type exhibit exceptional electrochemical stability towards lithium metal and possess a remarkable level of ionic conductivity, and thus are considered to be one of the most promising solid-state electrolytes for solid-state lithium-ion batteries. However, LLZO is unstable in humid air and reacts with H 2 O and CO 2 in the air to form Li 2 CO 3 , which reduces the wettability with lithium metal and decreases the overall ionic conductivity of LLZO. In this paper, a novel, fast, and simple method, lactic acid treatment, is proposed. The results show that Li 2 CO 3 on the LLZO surface can be completely removed by acid treatment for 30 seconds, resulting in a pure LLZTO surface and improved wettability with lithium metal. Meanwhile, the assembled lithium symmetric battery can be cycled stably for 240 hours at 0.2 mA/cm 2 .