Electrochemical characteristics and energy densities of lithium-ion batteries using mesoporous silicon and graphite as anodes

In order to fabricate high-energy and stable lithium-ion batteries (LIB), herein, mesoporous silicon (mpSiY) microparticles were prepared via a facile magnesiothermic reduction of commercial zeolite Y. The electrochemical characteristics of carbon-coated mpSi-Y (mpSi-Y/C) were evaluated in a lithium-ion battery full cell as well as a half-cell configuration and compared with those of silicon nanoparticle-carbon composite (SiNP/C) and graphite (Gr) anodes. With the mesoporous structural features of mpSi-Y, the high-capacity mpSi-Y/C (1200 mAh.g(-1) at 0.05 C) in a half-cell showed a much better cycling stability at a much less impedance build-up and electrode thickness increase than SiNP/C composite. It also presented much faster charging/discharging kinetics than does the graphite anode. A pretreated mpSi-Y/C was paired with a NCM (LiNi0.6Co0.2Mn0.2O2) cathode to fabricate a full cell, mpSi parallel to NCM. The mpSi parallel to NCM cell exhibited a comparable cycling performance to that of the Gr parallel to NCM cell at 0.5 C for 200 cycles. More importantly, detail analysis revealed that the size of the mpSi parallel to NCM cell can be smaller than that of the Gr parallel to NCM by more than 50%. The gain in specific energy density of the mpSi parallel to NCM cell over the Gr parallel to NCM was about 33%. Thus, the mpSi-Y/C can be promising anodes for stable and high-energy lithium-based batteries. (C) 2020 Elsevier Ltd. All rights reserved.