A dimensionally stable and fast-discharging graphite-silicon composite Li-ion battery anode enabled by electrostatically self-assembled multifunctional polymer-blend coatingElectronic supplementary information (ESI) available: Chemical formula of polymers, experimental, coulombic efficiency, SEM micrographs, and ac impedance measurements. See DOI: 10.1039/c4cc09825k

• Main Authors: Li, Fu-Sheng, Wu, Yu-Shiang, Chou, Jackey, Wu, Nae-Lih
• Format: Article
• Language: English
• ISSN: 1359-7345; 1364-548X
• DOI: 10.1039/c4cc09825k

A high-performance graphite-Si composite anode for Li-ion batteries containing Si nanoparticles (NPs) attached onto graphite microparticles was synthesized by adopting a polymer-blend of poly(diallyl dimethyl-ammonium chloride) and poly(sodium 4-styrenesulfonate). The polymer-blend enabled uniform distribution of Si NPs during synthesis and served as a robust artificial solid-electrolyte interphase that substantially enhanced the cycle stability and rate performance of the composite electrode. The electrode exhibited a specific capacity of 450 mA h g −1 , 96% capacity retention at a 10 C-rate, 95% retention after 200 cycles, and the same electrode expansion behavior as a pristine graphite electrode. A designed polymer blend enables the synthesis of a Si-on-graphite Li-ion battery anode with remarkably enhanced capacity, cycle and rate performance.