One-to-One Comparison of Graphite-Blended Negative Electrodes Using Silicon Nanolayer-Embedded Graphite versus Commercial Benchmarking Materials for High-Energy Lithium-Ion Batteries

5 years ago

One-to-One Comparison of Graphite-Blended Negative Electrodes Using Silicon Nanolayer-Embedded Graphite versus Commercial Benchmarking Materials for High-Energy Lithium-Ion Batteries

Jaephil Cho, Jiyoung Ma, Minseong Ko, Sujong Chae, Namhyung Kim

While existing carbonaceous anodes for lithium–ion batteries (LIBs) are approaching a practical capacitive limit, Si has been extensively examined as a potential alternative because it shows exceptional gravimetric capacity (3579 mA h g−1) and abundance. However, the actual implementation of Si anodes is impeded by difficulties in electrode calendering processes and requirements for excessive binding and conductive agents, arising from the brittleness, large volume expansion (>300%), and low electrical conductivity (1.56 × 10−3 S m−1) of Si. In one rational approach to using Si in high-energy LIBs, mixing Si-based materials with graphite has attracted attention as a feasible alternative for next-generation anodes. In this study, graphite-blended electrodes with Si nanolayer-embedded graphite/carbon (G/SGC) are demonstrated and detailed one-to-one comparisons of these electrodes with industrially developed benchmarking samples are performed under the industrial electrode density (>1.6 g cc−1), areal capacity (>3 mA h cm−2), and a small amount of binder (3 wt%) in a slurry. Because of the favorable compatibility between SGC and conventional graphite, and the well-established structural features of SGC, great potential is envisioned. Since this feasible study utilizes realistic test methods and criteria, the rigorous benchmarking comparison presents a comprehensive understanding for developing and characterizing Si-based anodes for practicable high-energy LIBs. Comparing the industrially developed benchmarking samples with synthesized Si nanolayer-embedded graphite/carbon hybrids in the graphite-blended electrode, Si nanolayer-embedded graphite/carbon exhibits the highest coulombic efficiency (CE 89.7%) at the first cycle, and cycling stabilization (CE >99.5%) is achieved after only second cycle, even with the least electrode volume expansion. This benchmarking comparison presents concrete guidelines and a comprehensive understanding of the implementation of Si anodes.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/aenm.201700071