Enhancing the performance of all-solid-state batteries

A collaborative research team from Pohang University of Science and Technology (POSTECH) and the POSCO N.EX.T Hub has enhanced the performance and durability of all-solid-state batteries through the implementation of a novel approach known as bottom electrodeposition. The team’s research findings were published in the journal Small.

Utilised in various applications such as electric vehicles and energy storage systems, secondary batteries generally rely on liquid electrolytes. However, the flammability of liquid electrolytes can pose a challenge. This has prompted ongoing research into the use of solid electrolytes and metal lithium (Li) in all-solid-state batteries, offering a safer option.

In the operation of all-solid-state batteries, lithium is plated onto an anode and the movement of electrons is harnessed to generate electricity. During the charging and discharging process, lithium metal undergoes a cycle of losing electrons, transforming into an ion, regaining electrons and being electrodeposited back into its metallic form. However, indiscriminate electrodeposition of lithium can quickly deplete the available lithium, leading to a reduction in the battery’s performance and durability.

To address this issue, the researchers collaborated with the POSCO N.EX.T Hub to develop an anode protection layer composed of a functional binder (PVA-g-PAA) for all-solid-state batteries. This layer exhibits exceptional lithium transfer properties, preventing random electrodeposition and promoting a process of bottom electrodeposition. This deposits the lithium uniformly from the bottom of the anode surface.

Using a scanning electron microscope (SEM), the researchers conducted an analysis that confirmed the stable electrodeposition and detachment of lithium ions. This reduced unnecessary lithium consumption. The all-solid-state batteries developed by the team also demonstrated stable electrochemical performance over extended periods, even with lithium metal as thin as 10 μm (micrometres) or less.

Professor Soojin Park, who led the research, said the team devised an enduring all-solid-state battery system through a novel electrodeposition strategy. “With further research, we aim to provide more effective ways to enhance battery life and increase energy density,” Park said.

POSCO Holdings now plans to move towards the commercialisation of lithium metal anodes, a core material for the next generation of secondary batteries.

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