Rapid Formation Strategy for Enhanced Electrochemical Performance of Hard Carbon Anodes in Sodium-Ion Batteries.

The conventional formation process of sodium-ion batteries (SIBs), which relies on low-current cycling, is one of the most energy-intensive and time-consuming steps in battery production, significantly contributing to overall manufacturing costs. This study systematically evaluates the formation of SIB pouch cells under different protocols and demonstrates that high-rate formation can achieve superior electrochemical performance. Our optimized high-rate formation process reduces formation time by 52.3% compared to the conventional method, presenting a cost-effective and efficient approach to SIB production. Notably, the accelerated formation process promotes the development of a denser, more uniform, and highly stable solid-electrolyte interphase (SEI) on the anode surface, enhancing initial Coulombic efficiency, capacity retention, and long-term cycling stability. These findings provide a promising strategy for improving the scalability and economic viability of SIB technology.