Solid-state batteries are becoming the new favorite, disrupting traditional technologies.
"Solid-state batteries that balance high energy density and high safety are not only the ultimate goal of battery technology, but are also gaining momentum globally," Dr. Che Yong, Vice General Manager and CTO of Enli Energy Technology Co., Ltd., told Science and Technology Daily on March 21.
Solid-state batteries are energy storage devices whose structure contains no liquid; all materials exist in solid form. They consist of a positive electrode material, a negative electrode material, and a solid electrolyte. Due to their advantages such as good safety performance, high energy density, and long cycle life, solid-state lithium batteries are ideal power batteries for electric vehicles.
Compared to lead-acid batteries, which have a 150-year history, lithium-ion batteries, which use organic electrolytes and entered industrialization in 1991, are still the most advanced batteries on the market.
"With the rapid advancement of modern materials science and manufacturing technology, battery technology in the 'post-lead and post-lithium' era has quietly arrived," said Che Yong. "In the near future, solid-state batteries will take firm steps into our society and change our lives."
Che Yong explained that solid-state batteries have significant advantages. Since solid electrolytes replace the potentially flammable organic electrolytes in traditional lithium-ion batteries, they solve the dilemma of high energy density and high safety, thereby eliminating the "range anxiety" of electric vehicle users and even potentially enabling fast charging.
To date, thanks to the continuous efforts of scientists, solid-state battery technology has largely overcome insurmountable technical bottlenecks, but some technical challenges remain to be solved. "The core technologies of solid-state batteries are solid electrolyte materials with high ionic conductivity and advanced manufacturing technologies for achieving low-impedance solid-solid interfaces," Che Yong further explained. Regarding solid electrolyte materials, Professor Ryoji Sugano of the Tokyo Institute of Technology invented a sulfide solid electrolyte in 2011 with an ionic conductivity >10⁻² S/cm at room temperature (surpassing traditional organic electrolytes).
Che Yong stated that this technology has become the technological foundation for Toyota Motor Corporation, a leading company in the industrialization of solid-state batteries. Compared to sulfide solid electrolytes, oxide solid electrolytes have advantages in terms of high safety and ease of production, but improving ionic conductivity at room temperature remains a major challenge.
