Constructing a Stable Si–N-Enriched Interface Boosts Lithium Storage Kinetics in a Silicon-Based Anode

Abstract

The stable operation of a SiO x anode largely depends on the intrinsic chemistry of the electrode/electrolyte interface; however, an unstable interface structure and undesirable parasitic reactions with the electrolyte of the SiO x anode often result in the formation of a fragile solid-electrolyte interphase (SEI) and serious capacity decay during the lithiation/delithiation process. Herein, a Si−N-enriched N-doped carbon coating is constructed on the surface of SiO x yolk−shell nanospheres (abbreviated as SiO x @NC) to optimize the SEI film. The two-dimensional covalently bound Si−N interface, on one hand, can suppress the interfacial reactivity of the SiO x anode to enable the formation of a thin SEI film with accelerated diffusion kinetics of ions and, on the other hand, acts as a Li + conductor during the delithiation process, allowing Li + to diffuse rapidly in the SiO x matrix, thereby improving the long-term cycling stability and rapid charge/discharge capability of the SiO x anode. A series of characterizations show that the interface chargetransfer barrier and the Li + diffusion energy barrier through the SEI film are the main factors that determine the interfacial electrochemical behavior and lithium storage performance. This work clarifies the relationship between the SEI characteristics and the interfacial transfer dynamics and aims to offer a more basic basis for the screening of other electrode materials.

Recent advances of SiO x -based anodes for sustainable lithium-ion batteries

“…Another effective coating method is conformal carbon coating by in-situ polymerization [93][94][95][96]. By in-situ polymerization to generate polymer precursors on the surface of SiO x and hightemperature pyrolysis, a uniform carbon coating on the SiO x surface could be successfully achieved.…”

“…Dopamine could easily selfpolymerize at alkaline environment and spontaneously deposit a uniform polydopamine coating on the surface of SiO x . After carbonization, nitrogen heteroatoms are introduced into the carbon coating in the form of pyridinic, pyrrolic, and quaternary nitrogen, thereby improving the reaction activity and electronic conductivity of nitrogen doped carbon [94]. Shi et al designed core-shell structured SiO x /nitrogen-doped carbon composites by conformal polymerization of dopamine and carbonization [94].…”

Constructing a Stable Conductive Network for High-Performance Silicon-Based Anode in Lithium-Ion Batteries

“…The C 1s spectra of Si@(POH-AOCNTs) can be decomposed into four peaks, corresponding to C–C, C–O, and OC bond and carbonate (−CO 3 ). The peaks of CO and Li 2 CO 3 are also recognized in the O 1s spectra. − Although similar peaks corresponding to C–C and C–O bonds are present in the C 1s spectra of Si@(PNH 2 -AOCNTs) after cycling, a relatively strong CO 3 peak at 289.6 eV can be clearly seen, whereas the peak strength of the OC bond at 288.2 eV is relatively weak, which indicates that more ethylene carbonate (EC) and diethyl carbonate (DEC) reduction and depletion have occurred on the Si@(PNH 2 -AOCNTs) electrode . In addition, the peaks at 684.9 and 687.2 eV in the F 1s spectra correspond to LiF and Li x PO y F z , respectively, Si@(POH-AOCNTs) shows a relatively strong peak of LiF compared to the Si@(PNH 2 -AOCNTs).…”

Synthesis of Organopolysilazane Nanoparticles as Lithium-Ion Battery Anodes with Superior Electrochemical Performance via the Two-Step Stöber Method

“…PDCs containing Si–C hybrid structures have electrochemical properties suitable for use as electrode materials for lithium-ion batteries . They are chemically inert, lightweight materials, and their chemical and physical properties can be structurally designed by varying the starting polymer composition. ,, Furthermore, the presence of N atoms in SiCNO Ps can enhance energy storage capacity and Li + transport by increasing electronic conductivity. − In order to study the difference of electrochemical properties between SiCNO ceramic NPs prepared by the Stöber method and SiCNO ceramic powder SiCNO HT prepared by the bulk hydrolytic polycondensation method, the active materials of SiCNO NPs and SiCNO HT were mixed with super P as anode materials for LIBs, respectively. The electrochemical performance of the composites was evaluated through a half-cell test, where the composite was used as a working electrode.…”