Tailoring Carbon Microcrystals for Ultrafast Lithium Storage

An effective carbon crystal regulation strategy is proposed by employing cationic molten salt as the shear agent and activator of the carbon layer. The shuttling of large-sized cations within the carbon skeleton can inhibit the graphitization and promote the evolution of microcrystalline or microporous structures, thereby significantly enhancing Li storage kinetics.

The demand for high energy density, fastcharging capability,and extended working life is crucial for next-generation lithium-ion batteries (LIBs) employed in consumer-grade electronic devices and electric vehicles.However, the presently utilized graphite anode exhibits sluggish ion kinetics and limited specific capacity owing to its fixed crystal structure and restricted interlayer distance. Herein, a large-size cation shear strategy for regulating carbon crystals is demonstrated. During the carbonization process, the shuttling of cations within the carbon skeleton inhibits the horizontal growth and longitudinal stacking of the carbon crystals, thereby successfully synthesizing ultramicrocrystalline carbon with short-range order and abundant microporous structures. As a result of the optimized carbon lattices, Li-ion insertion mechanism and dynamics are greatly improved, exhibiting a super high Li-storage capacity of 1156 mAh g⁻¹ at 0.1 A g⁻¹ (three times that of graphite theoretical capacity) and excellent rate capability with 375 mAh g⁻¹ maintained at 6 A g⁻¹ (100% graphite theoretical capacity). The assembled LiNi₆Co₂Mn₂-based full batteries achieve excellent fast charging capability and long cycle stability, with a 92% energy retention rate after 500 cycles. This carbon crystal regulation strategy demonstrates great potential for developing advanced carbon-based LIBs with high power and high energy.

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