Dual-ion battery (DIB) can potentially provide higher power, lower cost and faster charging capability than traditional lithium-ion batteries. Even though graphite can effectively accommodate anions as a cathode for DIB, the high working voltage of around 5 V vs. Li/Li⁺ leads to continuous side reactions, yielding to low Coulombic efficiency (CE < 90%) and poor cycle life. Here, we demonstrate that fluoroethylene carbonate (FEC) additive can induce a protective cathode electrolyte interface (CEI) on the graphite cathode, effectively suppressing electrolyte decomposition and stabilizing the graphite surface. This CEI enables a high CE (~99.0%) and an excellent cycle stability of 5000 cycles with capacity retention of 85.1% at the cutoff voltage of 5.1 V. The CEI layer can also reduce the self-discharge of the battery. Furthermore, the DIB exhibits a high-rate capability with 93.3% utilization at 30C (3000 mA g⁻¹), enabling an ultrafast charging time within two minutes. This work sheds light on the features of CEI on graphite cathodes and provides a facile and economically effective strategy to achieve highly reversible/stable cycling of DIBs with high power capability.

与传统的锂离子电池相比，双离子电池（DIB）可以提供更高的功率，更低的成本和更快的充电能力。尽管石墨可以有效地容纳阴离子作为DIB的阴极，但相对于Li / Li ^+而言，约5 V的高工作电压导致连续的副反应，导致库仑效率低（CE <90％）和较差的循环寿命。在这里，我们证明了氟代碳酸亚乙酯（FEC）添加剂可以在石墨阴极上诱导出保护性阴极电解质界面（CEI），从而有效地抑制了电解质的分解并稳定了石墨表面。该CEI可以实现高CE（〜99.0％）和5000个循环的出色循环稳定性，在5.1 V的截止电压下容量保持率为85.1％。CEI层还可以减少电池的自放电。此外，DIB表现出高速率能力，在30C（3000 mA g ^-1时的利用率为93.3％），可在两分钟内实现超快的充电时间。这项工作揭示了石墨阴极上CEI的特征，并提供了一种简便且经济有效的策略，以实现具有高功率能力的DIB的高度可逆/稳定循环。