An effective protocol for the fabrication of Ag-doped nano magnetic γ-Fe2O3@DA core–shell hollow spheres (h-Fe2O3@DA/Ag) by a simple hydrothermal method is demonstrated without any templates in the reaction system.

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Although Si and graphite (Si/C) composite materials are among the most promising alternative to graphite anode in commercial batteries because of high capacity, the issue of the poor structural and interfacial stability of the composite electrode is extremely challenging. Herein, an interface‐adaptive triblock polymer binder that can interact Si and graphite particles to improve the particle affinity and binder spreadability via the supramolecular interactions of π∙∙∙π stacking and hydrogen bonding is presented. The strategy of enhancing the interfacial interactions can further effectively stabilize the electrode interface and minimize the electrode/electrolyte side reactions. Benefiting from this proposed binder, the Si/C anode retains a high reversible capacity (82.1%) after 400 cycles and delivers improved cycling stability even at high areal capacity (4 mAh cm−2, 0.067% capacity loss/cycle) and in Si/C|LiNi0.8Co0.1Mn0.1O2 full cell (0.22% capacity loss/cycle). This design strategy for the binder provides a novel path toward high‐energy, long‐cycling Si/C anodes.

Silicon has attracted much attention as a promising anode material in lithium-ion batteries owing to its high specific capacity. However, silicon anode suffers large volume expansion during periodical lithiation/delithiation processes, leading to particle pulverization and thus electrochemical performance degradation. Herein, we report a water-soluble three-dimensional network polymer binder for silicon anode in which the introduced poly­(ethylene glycol) and divalent cation Ca2+ can form chemical cross-linking and physical cross-linking with poly­(acrylic acid), respectively. Poly­(ethylene glycol) serves as a soft segment to regulate the mechanical properties of the polymer, and the divalent cation Ca2+ acts as a physical cross-linking agent to form a dual network with poly­(acrylic acid). The multiple network binder owns good mechanical strength, strain resistance ability, and strong adhesion with Si particles and Cu collector, thereby preserving the stability of the silicon electrode. Therefore, silicon anode with this rationally designed binder exhibits excellent electrochemical performance with a discharge capacity of 1596 mAh/g after 800 cycles at a current density of 2 A/g. This design can provide a way to alleviate the volume expansion of the silicon anode and other high-capacity alloy anodes with large volume change for advanced batteries.

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