Silicon‐based (Si) materials are promising anodes for lithium‐ion batteries (LIBs) because of their ultrahigh theoretical capacity of 4200 mA h g⁻¹. However, commercial applications of Si anodes have been hindered by their drastic volume variation (∼300%) and low electrical conductivity. Here, to tackle the drawbacks, a hierarchical Si anode with double‐layer coatings of a SiO_x inner layer and a nitrogen (N), boron (B) co‐doped carbon (C–NB) outer layer is elaborately designed by copyrolysis of Si–OH structures and a H₃BO₃‐doped polyaniline polymer on the Si surface. Compared with the pristine Si anodes (7 mA h g⁻¹ at 0.5 A g⁻¹ after 340 cycles and 340 mA h g⁻¹ at 5 A g⁻¹), the modified Si‐based materials (Si@SiO_x@C–NB nanospheres) present superior cycling stability (reversible 1301 mA h g⁻¹ at 0.5 A g⁻¹ after 340 cycles) as well as excellent rate capability (690 mA h g⁻¹ at 5 A g⁻¹) when used as anodes in LIBs. The unique double‐layer coating structure, in which the inner amorphous SiO_x layer acts as a buffer matrix and the outer defect‐rich carbon enhances the electron diffusion of the whole anode, makes it possible to deliver excellent electrochemical properties. These results indicate that our double‐layer coating strategy is a promising approach not only for the development of sustainable Si anodes but also for the design of multielement‐doped carbon nanomaterials.

Solid-state polymer electrolytes (SPEs) have great processing flexibility and electrode–electrolyte contact and have been employed as the promising electrolytes for lithium metal batteries. Among them, poly(ethylene oxide) (PEO)-based SPEs have attracted widespread attention because of easy synthesis, low mass density, good mechanical stability, low binding energy with lithium salts, and excellent mobility of charge carriers. In order to overcome the low room-temperature ionic conductivity and the poor thermodynamic stability in high-voltage devices (>4.2 V) of the PEO materials, composition modulations by incorporating PEO with inorganic and/or organic components have been designed, which could effectively enable the applications of PEO-based SPEs with widened electro-stable voltage ranges. In this mini review, we describe recent progresses of several kinds of PEO composite structures for SPEs, and we compare the synthesis strategies and properties of these SPEs in lithium batteries. Further developments and improvements of the PEO-based materials for building better rechargeable batteries are also discussed.

Silicon (Si) has been counted as the most promising anode material for next-generation lithium-ion batteries, owing to its high theoretical specific capacity, safety, and high natural abundance. However, the commercial application of silicon anodes is hindered by its huge volume expansions, poor conductivity, and low coulombic efficiency. For the anode manufacture, binders play an important role of binding silicon materials, current collectors, and conductive agents, and the binder structure can significantly affect the mechanical durability, adhesion, ionic/electronic conductivities, and solid electrolyte interface (SEI) stability of the silicon anodes. Moreover, many cross-linked binders are effective in alleviating the volume expansions of silicon nanosized even microsized anodic materials along with maintaining the anode integrity and stable electrochemical performances. This mini review comprehensively summarizes various binders based on their structures, including the linear, branched, three-dimensional (3D) cross-linked, conductive polymer, and other hybrid binders. The mechanisms how various binder structures influence the performances of the silicon anodes, the limitations, and prospects of different hybrid binders are also discussed. This mini review can help in designing hybrid polymer binders and facilitating the practical application of silicon-based anodes with high electrochemical activity and long-term stability.

The world is facing an ever-growing global energy crisis with unprecedented depth and complexity. The sustainable development of high energy density lithium-ion batteries for electric vehicles and portable electric devices has become a feasible way to deal with this problem. Silicon suboxides (SiO_x) have been deemed as one of the most promising anode materials because of their ultrahigh theoretical lithium storage capacity, proper working potential, natural abundance, and environmental friendliness. However, the mass utilization of SiO_x-based anodes is severely obstructed by their low electrical conductivity and inevitable volume expansion. While lithium silicate and lithium oxide formed in the first lithiation process act as buffer layers to some extent, it is urgent to address the accompanying low initial Coulombic efficiency and unsatisfactory cycling stability. In this review, we summarized recent advances in the synthesis methods of SiO_x-based materials. Besides, the benefits and shortcomings of the various methods are briefly concluded. Then, we discussed the effective combination of SiO_x with carbon materials and designs of porous structure, which could considerably enhance the electrochemical performance in detail. Furthermore, progresses on the modified strategies， advanced characteristics and industrial applications for SiO_x-based anodes are also mentioned. Finally, the remaining challenges encountered and future perspectives on SiO_x-based anodes are highlighted.