Preparation and characterization of carbon cryogel (CC) and CC–SiO composite as anode material for lithium-ion battery

Abstract

Carbon cryogel (CC) has been prepared through sol–gel polycondensation of resorcinol (R) with formaldehyde (F) followed by freeze-drying and carbonization in this work. The characteristics and lithium-ion insertion–extraction property have been investigated for the first time. Based on the results that CC has very excellent cycling stability but very limited lithium-ion charge–discharge capacity, SiO is employed to synthesize CC–SiO composite by high energy mechanical ball-milling to improve the applicability. The results showed that, CC–SiO is composed of active carbon, graphite, SiO and dispersed Si crystal, while CC is composed of active carbon and graphite. CC–SiO has smaller and much more uniform particles than CC. SiO can greatly improve discharge capacity of CC with an acceptable sacrifice of cycling stability, and the charge–discharge capacity of CC–SiO comes mainly from lithium insertion–extraction in Si–SiO in the sample. CC–SiO has excellent high-rate discharge ability and is promising anode material of lithium-ion battery for use of high power density purpose.