NAMI and ATL have developed a separator-free lithium-ion battery (LIB) technology with a breakthrough nanofiber conformal coating on the electrode. The separator affects cell performance and safety. Reports show that the separator layer accounts for 7-10% of the price of the cell and the global demand for separators is expected to be over $1.3 million in 2025, indicating the importance and value of this polymer thin film in the battery design. The ultrathin and thermal stable nanofiber coating can provide the battery with high energy density, robust cycle and rate performances, leading the products in the market.
The achievement is attributed to the quadruple material properties, such as thickness reduction bringing electrodes in close proximity (<7um) but achieving desired dielectric performance. Superior adhesion to electrode (>10N/m), reducing the thickness change after long cycling, high porosity (>80%, max.) and superior electrolyte wettability for long and stable cycle performances. The separator-free design is achieved by skin coated nanofibers encapsulating the electrode. This architecture removes the need for a free-standing separator to achieve the best operating and safety performance.