![]() ![]() This “dynamic interfacing” is prone of worsening or blocking the electrical contact of the material by giving rise to undesirable side reactions between active material and electrolyte. Such a large volume change causes pulverization and electrical disconnection of the active material 15, but also forms dynamic interfaces 9, 16, 17, 18, 19. ![]() Thus, silicon possesses the highest theoretical gravimetric (specific) capacity, which is ten times that of commercial graphite (372 mAh g −1), but experiences up to 300% volume change upon lithiation and delithiation 6, 14. The high-capacity active materials inevitably suffer from large volume changes during charging and discharging processes (Fig. This electrical connection, at the same time, must be resistant to the electrolyte of a battery cell. The binding between such electrode materials and the adjacent electrically conductive media (e.g., carbon black) and consequently the electrode framework is a critical issue 9, 10, 11, 12, in particular when employing conventional electrode formulation with known conductive additives and binders 13. To meet the ever-demanding performance requirements of lithium-ion batteries (LIBs) and post-lithium rechargeable batteries for applications such as powering electric vehicles and integrating intermittent renewable energy, high-capacity electrochemically active electrode materials are being extensively exploited 1, 2, 3, 4, 5, 6, 7, 8. The results hold great promise for both further rational improvement and mass production of advanced energy storage materials. Combined with a simple, facile and scalable manufacturing process, this study opens a new avenue to stabilize silicon without sacrificing other device parameters. As evidenced by interfacial morphology and chemical composition, this design profoundly changes the interface between silicon and the electrolyte, securing the as-created contact to persist upon cycling. ![]() Different from existing strategies, the two-dimensional covalent binding creates a robust and efficient contact between the silicon and electrically conductive media, enabling stable and fast electron, as well as ion, transport from and to silicon. Their high reversibility, capacity and rate capability furnish a remarkable level of integrated performances when referred to weight, volume and area. Two-dimensional, covalently bound silicon-carbon hybrids serve as proof-of-concept of a new material design. Herein, a protocol is developed which we describe as two-dimensional covalent encapsulation. Stability improvements have been achieved, although at the expense of rate capability. The resulting instabilities of bulk and interfacial structures severely hamper performance and obstruct practical use. Silicon is a promising anode material for lithium-ion and post lithium-ion batteries but suffers from a large volume change upon lithiation and delithiation. ![]()
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