Rapid, tunable synthesis of porous carbon xerogels with expanded graphite and their application as anodes for Li-ion batteries.

The present work reports a rapid, tunable synthesis of resorcinol-formaldehyde (RF) carbon xerogels and their potential application as anode materials for lithium-ion battery. An iron-containing deep eutectic solvent (DES) is applied as both reaction medium and catalyst for the polymerization and graphitization. Water at different levels is employed as a co-solvent to mediate the polymerization and phase separation processes to produce a more-developed porous structure. The established binary-solvent synthesis strategy greatly simplifies the RF carbon xerogel preparation processes with a very short sol-gel time and a more acceptable ambient pressure drying. A duplex carbon configuration of rich microporosity (SBET = 566 m2 g-1) and expanded nanographite is achieved in the binary-solvent system with a DES mass fraction of 70%. The integrated structural merit is highly favorable for lithium storage, showing a reversible capacity of 633 mA h g-1 at 0.1 A g-1 and an excellent rate performance (205 mA h g-1 at 5 A g-1) as well as superior cycling stability.