Magnetically-Controlled Graphite Alignment for Fast and Stable Anion Intercalation

Dual-ion batteries (DIBs) are emerging as promising candidates for fast-charging electric vehicles owing to their ability to intercalate both cations and anions. However, increasing the energy density of DIBs, especially with thick graphite cathodes, remains a challenge due to structural instability during anion intercalation. In this study, a magnetically controlled method is introduced to vertically align graphite particles in thick electrodes, significantly improving the performance of DIBs. This novel architecture creates dense, low-tortuosity paths for fast anion transport and structural stability, allowing for high mass loadings exceeding 20 mg cm^-2. The vertically aligned graphite cathodes demonstrate a discharge capacity of 1.02 mAh cm^-2 at 5 C, retaining 85.6% capacity after 1000 cycles at 1 C, outperforming randomly and horizontally aligned graphite electrodes. Optimized electrodes also exhibit superior structural integrity and reduced formation of cathode electrolyte interphase compared to conventional designs. This study highlights the effectiveness of electrode architectural optimization in enhancing both energy density and fast-charging capabilities, providing a straightforward approach to developing next-generation DIBs with high performance and stability for practical applications in electric vehicles.