Search

A stable interface between silicon anodes and electrolytes is vital to realizing reversible electrochemistry cycling for lithium‐ion batteries. Herein, a zincone polymer coating is controllably deposited on a silicon electrode using the molecular layer deposition to serve as an artificial solid electrolyte interphase (SEI). Enhanced electrochemical cycling depends on the thickness of zincone coating. The optimal zincone coating of ≈3 nm markedly improves the lithium storage performance of silicon anodes, resulting in a high reversible capacity (1741 mA h g−1 after 100 cycles at 200 mA g−1), outstanding cycling stability (1011 mA h g−1 after 500 cycles), and superior rate capability (1580 mA h g−1 at 2 A g−1). Such remarkable electrochemical reversibility stems from the in situ conversion of the zincone coating and a zincone‐driven thin lithium fluoride (LiF)‐rich SEI, which endow the silicon electrode with superior electron/ion transport and structural stability. Meanwhile, the zincone coating demonstrates good compatibility with ether‐based electrolytes (893 mA h g−1 after 200 cycles, 970 mA h g−1 at 5 A g−1). Additionally, in situ conversion of artificial zincone coating also opens a door for constructing a functional interface on other electrode surfaces, such as lithium/sodium metal. [ABSTRACT FROM AUTHOR]

Establishing a stable electrode-electrolyte interface (SEI) is extremely critical to achieving a reversible silicon anode for lithium ion batteries. Herein, a conformal polyurea layer with hydrogen bonds and polar functional groups is firstly controllably constructed on the silicon electrode as an artificial SEI via molecular layer deposition. The optimized polyurea coating of ∼3 nm greatly promotes the electrochemical lithium storage performance of silicon anodes, including highly reversible cycling stability (1010 mA h g−1 after 1000 cycles) and rate capability (1820 mA h g−1 at 2 A g−1, 1420 mA h g−1 at 5 A g−1). Analyses show that this polyurea layer can greatly promote lithium ions diffusion kinetic in the silicon electrodes and induce a stable, thin, and LiF-rich SEI with good mechanical stability. Moreover, this polyurea coating shows a significant improvement for larger-size silicon particles (even >150 nm) and superior compatibility with ether-based electrolytes. Notably, the full cells paired with LiFePO 4 cathode exhibit impressive cycling stability with a high energy density of 453 Wh kg−1. This work provides constructive guidance for constructing a stable artificial SEI for silicon anodes. [Display omitted] • A conformal polyurea layer is firstly controllably constructed on the silicon electrode. • Polyurea can promote lithium ions diffusion kinetic in the silicon electrodes. • Polyurea can induce a stable, thin, and LiF-rich SEI with good mechanical stability. • ∼3 nm polyurea layer greatly promotes the electrochemical performance of silicon anodes. [ABSTRACT FROM AUTHOR]

Silicon anodes have attracted enormous attention with the merits of outstanding theoretical capacity for high-energy-density lithium-ion batteries. However, the drastic volume variation will destroy the structural integrity of the electrode system during the alloying/dealloying process. Herein, based on the supramolecular self-assembly, a multifunctional dynamic cross-linking strategy with self-healing chemistry and enhanced ionic conductivity for silicon electrode network structure is rationally designed by amino-functionalized silicon (Si-NH 2) and dopamine-modified poly(acrylic acid) (PAA-DA). Dynamic reversible hydrogen bonds and ionic bonds are formed by random cross-linking of the primitives carried by the material, which endow the electrode with rapid self-healing ability and strong adhesion, and provide a continuous internal pathway for the electrode system. Moreover, the presence of polar groups can beneficially heighten the transport kinetics of lithium ions. The prepared Si-NH 2 @PAA-DA electrode displays excellent high-rate capability with a reversible capacity of 2671.6 mAh g−1 at 1 C (1 C = 4000 mA g−1) and superior cycle stability (2160.1 mAh g−1 after 100 cycles at 400 mA g−1). Therefore, this design idea with dynamic reversible and multi-crosslink network structure provides in-depth insights for the advancement of the next-generation high-energy-density batteries. [Display omitted] • Multifunctional dynamic cross-linking strategy (Si-NH 2 @PAA-DA) with self-healing chemistry and enhanced ionic conductivity for silicon electrodes is successfully designed. • Multiple dynamic supramolecular interactions (hydrogen bond and ionic bond) can effectively dissipate the stress-energy of volume change and relieve the mechanical cracking of the electrode. • The presence of polar groups can beneficially heighten the transport kinetics of lithium ions. • Si-NH 2 @PAA-DA electrode exhibits outstanding cycling stability and rate performance. [ABSTRACT FROM AUTHOR]