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In order to improve the electrochemical properties of nano Si-carbon composites, a binder-free Si-CNTs composite with good dispersion of Si nanoparticles were prepared by ionic liquids self-assembly method. [Display omitted] • A binder-free Si-CNTs composites were prepared by ILs assisted self-assembly method. • The as-prepared Si-CNTs composites show ball-like structure, and the SiNPs are dispersed in the carbon nanotubes self-assembly uniformly. • The carbon nanotubes could be self-assembled into a 3D structure through electrostatic gravitational force of ILs, and the heteroatoms of ILs could dope in the carbon skeleton during annealing. • ILs plays an important role in the dispersion of SiNPs in Si-CNTs system. • Si30%-CNTs exhibit excellent cycle performance and rate capability. Binder-free nano silicon/carbon nanotube composites anodes were synthesized by electrostatic self-assembly of ionic liquids (ILs) and annealing process. The addition of [Emim]Tf 2 N ILs successfully improved the dispersion of silicon nanoparticles (SiNPs) in the carbon nanotubes (CNTs). And the carbon nanotubes could be self-assembled into a 3D structure network through electrostatic gravitational force. Moreover, the wettability of electrode also be improved due to the heteroatoms of [Emim]Tf 2 N ILs doped in the CNTs during annealing. By integrating these advantages, the Si30%-CNTs anodes exhibit a high initial reversible discharge capacity of 2580.3 mAh g−1 at a current density of 0.4 A g−1. Even at a much higher current density of 10 A g−1, the Si30%-CNTs anodes can still deliver a high reversible discharge capacity of 871.1 mAh g−1. The outstanding performances compared to traditional coating method are assigned to that the ionic liquids self-assembly method improves the dispersion of SiNPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel PDDA/GO dual-layer coating strategy to effectively improve the performance of NCM811 is proposed in this paper. • NCM811 particles can be well-encapsulated in the resultant dual-layer by a simple electrostatic adsorption method. • The PDDA/GO coating depresses the LiF component, enables a homogeneous organic-enriched CEI film with fast Li diffusion and effective corrosion protection on cathodes. • NCM811-PDDA/GO cathodes exhibit a 77% capacity retention after 500 cycles at the current density of 50 mA g−1, against 28% for pristine NCM811. Cathode-electrolyte interphases (CEIs) are determinative to the electrochemical performance of lithium-ion batteries, especially those with Ni-rich cathodes. Herein, we employed the simple electrostatic adsorption (SEA) method to generate a homogenous polydimethyldiallyl ammonium chloride/ graphene oxide (PDDA/GO) dual-layer coating on the surface of a model single-crystalline Ni-rich cathode, LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), and thus modified the CEIs in both compositions and microstructures. The PDDA/GO coating depresses the LiF component, enables a homogeneous organic-enriched CEI film with fast Li diffusion and effective corrosion protection on cathodes. Together with the mechanical confinement on cathodes, these characters of modified CEIs benefit the electrochemical stability effectively. For instance, NCM811-PDDA/GO cathodes exhibit a 77% capacity retention after 500 cycles at the current density of 50 mA g−1, against 28% for pristine NCM811. This study provides new insights in correlating the coating and CEIs, which effectively guide the development of Ni-rich cathodes for high performance. Such a simple strategy to form a homogeneous coating can also be extended into other electrode materials easily. [ABSTRACT FROM AUTHOR]