"Pre-ionization assisted synthesis of tailored magnesium‑aluminum bimetallic metal-organic framework-derived carbon with controlled layer spacing and porosity for performance supercapacitor and sodium-ion battery."

Precise control of particle size, pore size distribution, and carbon layer spacing under green and low-energy conditions is critical for developing advanced carbon electrodes for supercapacitors and sodium-ion batteries (SIBs). Herein, we proposed a new strategy to prepare an MgAl bimetallic metal-organic framework (MOF) via a pre-ionization strategy, effectively avoiding harsh conditions and using organic solvents in hydrothermal synthesis. By fine-tuning the Mg/Al ratio and pyrolysis conditions, the particle size, pore size distribution and carbon layer spacing of rod porous carbon (RPC) were precisely adjusted. The optimized RPC-2 material demonstrated an outstanding specific capacitance of 434 ± 4 F g^-1 at 1 A g^-1 in 6 M KOH and maintained 96 % after 100,000 cycles. Besides, the RPC-2 based SIBs exhibited excellent reversible capacity (339 ± 3 mAh g^-1 at 100 mA g^-1) and durability (91 % capacity retention after 4500 cycles at 5 A g^-1), indicating excellent performance and stability for supercapacitors and SIBs. The results reveal that the layered porous structure, micro/mesopores, moderate graphitization and optimized carbon layer spacing greatly increase its electrical conductivity and Na⁺ diffusion speed. This work not only avoids the requirements of high temperature and high pressure during the MOF synthesis but also eliminates the consumption of activating agents and organic solvents, providing an environmentally friendly and scalable pathway for designing hierarchical porous carbon electrodes in high-performance supercapacitors and SIBs.