In situ-formed nitrogen-doped carbon/silicon-based materials as negative electrodes for lithium-ion batteries

The development of negative electrode materials with better performance than those currently used in Li-ion technology has been a major focus of recent battery research. Here, we report the synthesis and electrochem-ical evaluation of in situ-formed nitrogen-doped carbon/SiOC. The materials were synthesized by a sol-gel pro-cess using 3-(aminopropyl)triethoxysilane (APTES), sodium citrate and glycerol. The electrochemical performance of pyrolyzed materials was studied using poly(acrylic acid) binder and commercial organic elec-trolyte. Our reported approach enables changes in both the amount of nitrogen and the morphology as a func-tion of the molar ratio of APTES:citrate and reaction time. Spherical-shaped NC/SiOC composite electrodes deliver a delithiation capacity of 622 mAh/g at 0.1 A/g and an initial coulombic efficiency of-63%, while in the large bulk material, respective values of 367 mAh/g and-55% were obtained. After 1000 charge/dis-charge cycles at 1.6 A/g, the latter material exhibits 98% of the initial capacity once it returned to lower cur-rent cycling. Overall, our results indicate that NC/SiOC materials are quite promising for electrochemical applications since both their large capacity and stability demonstrate superior performance compared to tradi-tional graphite. Moreover, our synthesis is simple and, more importantly, environmentally friendly chemicals, such as sodium citrate and glycerol, are used.