Lithium metal is expected to become the ultimate anode material for all-solid-state batteries

Scientists from Tohoku University and the High Energy Accelerator Research Organization in Japan have reportedly developed a new composite hydride lithium superion conductor. The researchers said that this new material, which was achieved by designing the hydrogen cluster (composite anion) structure, showed extremely high stability to lithium metal, making lithium metal likely to become the final anode material for all-solid-state batteries, giving birth to the all-solid-state battery with the highest energy density to date.

All-solid-state batteries with lithium metal anodes are expected to solve the problems of electrolyte leakage, flammability and limited energy density of traditional lithium-ion batteries . It is generally believed that lithium metal is the best anode material for all-solid-state batteries because it has the highest theoretical capacity and the lowest potential among known anode materials.

Lithium-ion conducting solid electrolytes are a key component of all-solid-state batteries, but the problem is that most existing solid electrolytes are chemically/electrochemically instable, which inevitably causes unwanted side reactions at the interface, leading to increased interfacial resistance and greatly reducing the performance of the battery during repeated charge and discharge.

The researchers said that complex hydrides have attracted widespread attention in solving the problems associated with lithium metal anodes because they have excellent chemical and electrochemical stability to lithium metal anodes. The new solid electrolyte they obtained not only has high ionic conductivity but is also very stable to lithium metal, so it is a real breakthrough for all-solid-state batteries using lithium metal anodes.

The researchers said: "This development will not only help us find lithium-ion conductors based on complex hydrides in the future, but will also open up a new trend in the field of solid electrolyte materials. The resulting new solid electrolyte materials are expected to promote the development of high-energy-density electrochemical devices."

Electric vehicles expect high energy density and safe batteries to achieve satisfactory driving range. If the electrodes and electrolytes cannot cooperate well in terms of electrochemical stability, there will always be a hurdle on the road to popularization of electric vehicles. The successful cooperation between metallic lithium and hydride has opened up new ideas. Lithium is indeed full of potential. Electric vehicles with a range of thousands of kilometers and smartphones with a week of standby time may not be far away.