Researchers from USTC proposed a new technical route to unleash the potential of all-solid-state lithium batteries

Battery technology is one of the core technologies of "dual carbon" such as new energy vehicles and energy storage. All-solid-state lithium batteries use non-flammable inorganic solid electrolytes instead of organic liquid electrolytes. Compared with commercial lithium-ion batteries, they have higher safety and greater room for energy density improvement, so they have become the research focus of the next generation of lithium batteries.

A reporter recently learned from the University of Science and Technology of China that Professor Ma Cheng of the school has proposed a new technical route for all-solid-state battery positive electrode materials, which can greatly increase the active material loading in the composite positive electrode, thereby giving full play to the energy density potential of all-solid-state lithium batteries.

According to researchers, in order to fully exert the performance of all-solid-state batteries, the cathode materials must meet at least two conditions: excellent ionic conductivity and good deformability. However, these two points are difficult to achieve in oxide materials such as lithium cobalt oxide and lithium iron phosphate used in current commercial lithium-ion batteries.

In this study, Ma Cheng's research group adopted an unconventional material design approach and selected chlorides to construct a new positive electrode material for all-solid-state lithium batteries - lithium titanium chloride.

Research has found that lithium titanium chloride is extremely soft and can reach a relative density of more than 86.1% as long as it is cold pressed. In addition, its room temperature ion conductivity is as high as 1.04 millisiemens per centimeter, far exceeding that of oxide cathode materials, and even comparable to solid electrolyte materials that are mainly responsible for ion transport in batteries. Therefore, the composite cathode based on lithium titanium chloride can achieve an active material loading of 95% by mass, far exceeding the limits of oxide cathodes such as lithium iron phosphate and lithium cobalt oxide in all-solid-state batteries.

Research results show that chloride positive electrode materials represented by lithium titanium chloride are very promising positive electrode "candidates" in all-solid-state lithium batteries, and can further unleash the potential of all-solid-state batteries in terms of energy density.

Recently, the research results were published in the internationally renowned academic journal Nature Communications.