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The commercialized binder carboxymethyl cellulose sodium (CMC-Na) is considered unsuitable for micro-sized SiOx anode as it cannot endure the large volume change to retain the conductive network during repeated charge/discharge cycles. Herein, a small amount of silicon nano particles (SiNPs) is added during slurry preparation process as “nano-combs” to unfold the convoluted CMC-Na polymer chains so that they undergo a coil-to-stretch transition by interaction between polar groups (e.g -OH, -COONa) of polymer and SiNPs’ large surface. Through maximizing the utilization of binders, a uniform conductive network is constructed with increased interfacial contact with micro-sized SiOx. As a result, the SiOx electrode with optimized (10 wt%) SiNPs addition shows significantly improved initial capacity as well as cycling performance. Through revisiting CMC-Na, a currently deemed unqualified binder in SiOx anode, this work gives a brand-new perspective on the failing mechanism of Si-based anode materials as well as an improving strategy for electrode preparation.

Due to the severe volume variations during electrochemical processes, Si-based anodes suffer from poor cycling performance as the result of a collapsed conductive network. In this regard, a key strategy for fully exploiting the capacity potential of Si-based anodes is to construct a robust conductive network through rational binder design. In this work, a bio-inspired conductive binder (PFPQDA) is designed by introducing dopamine-functionalized fluorene structure units (DA) into a conductivity enhanced polyfluorene-typed copolymer (PFPQ) to enhance its mechanical properties. Through constructing hierarchical binding networks and resilient electron transportations within both nano-sized Si and micro-sized SiO

In this paper, MnO-carbon hybrid nanofibers are fabricated via an electrospinning method, while polyvinyl alcohol (PVA) and manganese acetylacetonate are used as raw materials. Composition, phase structure, and morphology of the products obtained under different sintering temperatures are studied with modern analytical instruments, and the electrochemical properties of the MnO/C fibers used as the lithium ion battery anode are also studied by continuous charge/discharge procedures. The results demonstrate that sintering temperature has an important influence on the performance of the obtained composites, and there is an optimum value for synthesizing MnO/C composites. Material synthesized under 600 °C can exhibit an ideal fiber appearance with MnO particles embedded into the material and deliver the highest capacity among all samples. The formation mechanism of the materials is also analyzed in detail in this paper.

This report unravels the dependence of the microstructure and electrochemical performances of Li-rich layered transition metal oxide (LLMO) on the molecular structure of polymer templates for the formation of oxalate precursor. A representative LLMO, Li1.2Mn0.54Ni0.13Co0.13, is synthesized by co-precipitation method, and three samples, LLMO-PVP, LLMO-PEG and LLMO-PVA, are obtained with polymer templates, polyvinyl pyrrolidone (PVP), polyethyleneglycol (PEG) and polyvinyl alcohol (PVA), respectively. The physical and chemical properties of the resulting products are analyzed with SEM, TEM, XRD, BET, ICP, and XPS, and their electrochemical performances as cathode of Li-ion battery are evaluated with EIS, GITT and charge/discharge tests. It is found that LLMO-PVP exhibits the best performances, followed by LLMO-PEG, while LLMO-PVA behaves poorest. This difference is ascribed to the various microstructures of the resulting products, which are determined by the molecular structure of polymer templates.

Despite exhibiting high specific capacities, Si-based anode materials suffer from poor cycle life as their volume change leads to the collapse of conductive network within the electrode. For this reason, the challenge lies in retaining the conductive network during electrochemical processes. Herein, to address this prominent issue, a cross-linked conductive binder (CCB) is designed for commercially available silicon oxides (SiOx ) anode to construct a resilient hierarchical conductive network from two aspects: on the one hand, exhibiting high electronic conductivity, CCB serves as an adaptive secondary conductive network in addition to the stiff primary conductive network (e.g., conductive carbon), facilitating faster interfacial charge transfer processes for SiOx in molecular level; on the other hand, the cross-linked structure of CCB shows resilient mechanical properties, which maintains the integrity of the primary conductive network by preventing electrode deformation during prolonged cycling. With the aid of CCB, untreated micro-sized SiOx anode material delivers an areal capacity of 2.1 mAh cm-2 after 250 cycles at 0.8 A g-1 . The binder design strategy, as well as, the relevant concepts proposed herein, provide a new perspective toward promoting the cycling stability of high-capacity Si-based anodes.

Poly(ethylene oxide) (PEO) is a promising solid electrolyte material for solid-state lithium–sulfur (Li–S) batteries, but low intrinsic ionic conductivity, poor mechanical properties, and failure to hinder the polysulfide shuttle effect limits its application. Herein, a polymer of intrinsic microporosity (PIM) is synthesized and applied as an organic framework to comprehensively enhance the performance of PEO by forming a composite electrolyte (PEO-PIM). The unique structure of PIM-1 not only enhances the mechanical strength and hardness over the PEO electrolyte by an order of magnitude, increasing stability toward the metallic lithium anode but also increases its ionic conductivity by lowering the degree of crystallinity. Furthermore, the PIM-1 is shown to effectively trap lithium polysulfide species to mitigate against the detrimental polysulfide shuttle effect, as electrophilic 1,4-dicyanooxanthrene functional groups possess higher binding energy to polysulfides. Benefiting from these properties, the use of PEO-PIM composite electrolyte has achieved greatly improved rate performance, long-cycling stability, and excellent safety features for solid-state Li-S batteries. This methodology offers a new direction for the optimization of solid polymer electrolytes.