Key Factors for Binders to Enhance the Electrochemical Performance of Silicon Anodes through Molecular Design.

Silicon is considered the most promising candidate for anode material in lithium-ion batteries due to the high theoretical capacity. Unfortunately, the vast volume change and low electric conductivity have limited the application of silicon anodes. In the silicon anode system, the binders are essential for mechanical and conductive integrity. However, there are few reviews to comprehensively introduce binders from the perspective of factors affecting performance and modification methods, which are crucial to the development of binders. In this review, several key factors that have great impact on binders' performance are summarized, including molecular weight, interfacial bonding, and molecular structure. Moreover, some commonly used modification methods for binders are also provided to control these influencing factors and obtain the binders with better performance. Finally, to overcome the existing problems and challenges about binders, several possible development directions of binders are suggested.

Mg ion pre-intercalated MnO2 nanospheres as high-performance cathode materials for aqueous Zn-ion batteries.

Rechargeable Zn-MnO2 batteries with mild and nearly neutral aqueous electrolytes have shown great potential for large-scale energy storage because of their high safety, low cost, environmental friendliness and high energy density. However, MnO2 cathode materials usually have disadvantages such as low capacity and poor cycling stability, which limit the development of Zn-MnO2 batteries. In this study, mesoporous MnO2 nanospheres were prepared by in situ Mg ion pre-intercalation via a simple chemical method. The prepared MnO2 shows a high reversible capacity (247 mA h g-1 at 0.3 A g-1), excellent cycling stability (a capacity retention of 93% over 800 cycles at 0.8 A g-1) and good rate performance. The GITT, in situ EIS, ex situ XRD, ex situ XPS and ex situ SEM show that the zinc storage mechanism of MnO2 should be H+/Zn2+ co-intercalation/de-intercalation. This research could provide specific inspiration and promotion for the development and mechanism research of high-performance rechargeable Zn-MnO2 batteries.