Metal oxides have been regarded as promising next-generation anode materials for rechargeable lithium ion batteries; however, their poor stability, which is caused by large volume changes during repeated lithiation/delithiation, remains a challenge. Here, conformally encapsulated low-oxidation state oxide cubes with reduced graphene oxide (RGO) obtained via a new pressurized reduction consisting of external mechanical compression and internal thermokinetic reduction from highly porous metal oxides/RGO aerogel (RGOA) are reported. Using single crystalline (SC) cobalt oxides and iron oxide cubes as model systems, the SC-Co3O4 or Fe2O3 cube/RGOA are pressurized into compacted xerogel along with a uniform thermokinetic reduction, which result in topotactic transformation to core-shelled CoO/RGO or Fe3O4@RGO cubes. The SC-CoO and SC-Fe3O4 cubes isolated perfectly in the RGO shells have dramatically improved their cycling stabilities for lithium ion storage to hundreds of times. The lithium-ion storage stability of the core/shelled low-oxidation state oxide/RGO cubes can be prolonged by at least 400 times.
Bibliographical noteFunding Information:
K.Z. and P.L. contributed equally to this work. This work was supported by the NRF of Korea Grant funded by the Ministry of Science, ICT & Future Planning (NR-2013R1A2A1A09014038) and the Energy Efficiency & Resources Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (20152010103470).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics