An ultrahigh-areal-capacity SiOx negative electrode for lithium ion batteries

Constructing a stable microstructure is highly crucial in promoting the practical applications of Si-based negative electrodes , addressing the issues of huge volume change and unstable solid electrolyte interface (SEI). Herein, an integrated electrode structure is developed based on micro-sized SiO x particles by bilayers coating of carbon and poly(3,4-ethylene dioxythiophene) (PEDOT) with carbon nanotube/Super P conductive network in-situ embedded (SiO x @C@P_CS). The as-prepared SiO x @C@P_CS negative electrode exhibits high Coulombic efficiency reaching 99.9% and capacity retentions of 86.7% (1019 mAh g −1 ) after 1000 cycles at 750 mA g −1 and 98.4% (973 mAh g −1 ) after 400 cycles at 1500 mA g −1 (with a commercial-level areal capacity of 2.57 mAh cm −2 ). The excellent long cycling capability is further evidenced both in half cell with ultrahigh areal capacity up to 11.75 mAh cm −2 at the mass loading of 8.66 mg cm −2 and Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 (NCM811)||SiO x @C@P_CS full cell with commercial loading. The improved electrochemical performance is attributed to the synergistic effects of the bilayers. This study offers a facile solution to the challenges facing alloying-type negative electrode materials with huge volume changes by confining volume change, enhancing electric conductivity , and isolating the growth of SEI to promote their practical uses.