Peng Dou

One-Step Electrochemical Growth of a Three-Dimensional Sn–Ni@PEO Nanotube Array as a High Performance Lithium-Ion Battery Anode

Various well-designed nanostructures have been proposed to optimize the electrode systems of lithium-ion batteries for problems like Li(+) diffusion, electron transport, and large volume changes so as to fulfill effective capacity utilization and increase electrode stability. Here, a novel three-dimensional (3D) hybrid Sn-Ni@PEO nanotube array is synthesized as a high performance anode for a lithium-ion battery through a simple one-step electrodeposition for the first time. Superior to the traditional stepwise synthesis processes of heterostructured nanomaterials, this one-step method is more suitable for practical applications. The electrode morphology is well preserved after repeated Li(+) insertion and extraction, indicating that the positive synergistic effect of the alloy nanotube array and 3D ultrathin PEO coating could authentically optimize the current volume-expansion electrode system. The electrochemistry results further confirm that the superiority of the Sn-Ni@PEO nanotube array electrode could largely boost durable high reversible capacities and superior rate performances compared to a Sn-Ni nanowire array. This proposed ternary hybrid structure is proven to be an ideal candidate for the development of high performance anodes for lithium-ion batteries.

A coral-inspired nanoscale design of Sn–Cu/PANi/GO hybrid anode materials for high performance lithium-ion batteries

A facile and scalable synthesis approach is developed for fabrication of a three-dimensional (3D) polyaniline (PANi)/graphene oxide (GO) hybrid hydrogel evenly embed with hollow Sn–Cu nanoparticles (Sn–Cu NPs) as high performance anode for lithium-ion batteries. The hierarchical conductive hydrogel was prepared via in situ polymerization of aniline monomer on the surface of Sn–Cu NPs and GO nanosheets. The morphology and structure of the resulting hybrid materials have been characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hierarchical conductive hydrogel framework with dendritic PANi nanofibers and 2D GO nanosheets serve as a continuous 3D electron transport network and high porosity to accommodate the volume expansion of Sn–Cu NPs. The PANi coating plays an “artificial SEI” function to preserve the structural and interfacial stabilization of Sn–Cu NPs during the cycling processes. As a consequence of this 3D hybrid anode, an extremely long stable cycling performance is achieved with reversible discharge capacity over 693 mA h g−1 after 200 cycles at current rate of 0.2 C and a reversible capacity of 371 mA h g−1 retention at a much higher current rate of 2 C, suggesting that this novel Sn–Cu/PANi/GO composite is a promising candidate for energy storage applications.

Three-dimensional ultrathin Sn/polypyrrole nanosheet network as high performance lithium-ion battery anode

In order to optimize the electrode system of lithium-ion batteries for problems such as lithium ion diffusion, electron transportation, and large volume changes during cycling processes, a novel anode material composed of ultrafine Sn nanoparticles (∼5 nm) anchored inside a well-connected three-dimensional (3D) polypyrrole (PPy) nanosheet network has been designed and synthesized through a simple microemulsion-based preparation of tin nanoparticles with organic crystal surface-induced PPy polymerization. In this electrode material, the ultrathin PPy coating (∼3–4 nm) plays a “flexible confinement” function to preserve the structural and interfacial stabilization of inner Sn nanoparticles as well as a “binder” function to suppress the detachment of Sn from the collector. Meanwhile, the continuous conductive PPy nanosheet network with open structures and large contact surface for Sn nanoparticle dispersion can provide easy access for Li+ intercalation. As a result, the integration of a 3D conductive network and ultrafine Sn nanoparticles with an ultrathin in situ PPy coating induces improved structural integrity and accessible capacity for Sn nanoparticle electrodes. It delivered a high capacity retention of 766 mA h g−1 after 200 cycles at the current density of 0.2 A g−1 and a reversible capacity of 583 mA h g−1 when kept at a much higher current density of 2 A g−1.

Correction: Self-supported Co3O4 nanoneedle arrays decorated with PPy via chemical vapor phase polymerization for high-performance detection of trace Pb2+

Correction for ‘Self-supported Co3O4 nanoneedle arrays decorated with PPy via chemical vapor phase polymerization for high-performance detection of trace Pb2+’ by Wenjing Wang et al., Anal. Methods, 2017, 9, 1905–1911.

Synthesis of Sn–Co@PMMA nanowire arrays by electrodeposition and in situ polymerization as a high performance lithium-ion battery anode

Transition metals have attracted much attention due to their high energy density in lithium-ion batteries (LIBs). However, the huge volume change and the fast capacity fading still limit their application. If the microstructure of the electrode materials can be designed properly, the volume change problems encountered during lithiation and delithiation could be alleviated to some extent. Here, novel three-dimensional (3D) hybrid Sn–Co nanowire arrays coated by poly(methyl methacrylate) (Sn–Co@PMMA NWs) are synthesized via a simple electrodeposition method followed by in situ emulsion polymerization. The electrode structure is well preserved after repeated Li-ion insertion/extraction, indicating that the positive synergistic effect of the Sn–Co NWs and uniform PMMA layer could effectively accommodate the volume expansion of tin anode materials. The electrochemistry results demonstrate that the Sn–Co@PMMA NWs electrode exhibits a high reversible capacity, a high initial coulombic efficiency, a good rate capability, and an improved capacity retention compared with the bare Sn–Co NWs electrode. This proposed nanoengineering strategy is proven to be an ideal candidate for the development of high performance anode for LIBs.

Hollow Sn–Ni nanoparticles coated with ion-conductive polyethylene oxide as anodes for lithium ion batteries with superior cycling stability

A facile strategy is designed for the fabrication of hollow, Sn–Ni nanoparticles (NPs) surrounded by ion-conductive, polyethylene oxide (PEO) coating to address the structural and interfacial stability concerns facing Sn-based anodes. In the unique architecture of hollow Sn–Ni@PEO NPs, the ductile inactive Ni as a buffer matrix can alleviate the volume change of Sn. Moreover, the synergistic effect between the elastic ion-conductive PEO coating and the hollow interior forces the active Sn to expand inward into the hollow space in the lithiated state, and thus effectively accommodates the substantial volume expansion. In particular, the PEO coating not only suppresses the unfavorable aggregation and pulverization of Sn during cycling, but also helps in forming a stable solid electrolyte interface (SEI) film on the high surface area nanostructured electrodes. Benefiting from the structural features, hollow Sn–Ni@PEO NPs exhibit a reversible capacity of 584 mA h g−1 after 100 cycles with excellent coulomb efficiency of higher than 99%, superior to the bare counterparts. The contribution to the excellent cycling performance by the PEO coating and the hollow structure is verified by galvanostatic charge/discharge cycling, cyclic voltammetry, electrochemical impedance spectroscopy and SEM measurements.

Bubble-induced lychee-shaped hollow ZnCo2O4@polypyrrole/sodium alginate ternary microsphere as novel anode materials for lithium-ion batteries

We designed the hollow ZnCo2O4 microsphere with meshy surface by means of ormaldehyde bubble-induced method. To avoid the occurring of the side reaction on the interface caused by its high specific surface area, three-dimensional (3D) polypyrrole/sodium alginate (PPy/SA) composite via the situ polymerization of pyrrole in an aqueous solution of SA was used as the coating layer of ZnCo2O4 to form lychee-shaped ZnCo2O4@PPy/SA microsphere. The PPy/SA was found to have a more favorable conductivity and mechanical strength than PPy. As anode material for lithium-ion battery, ZnCo2O4@PPy/SA possesses numerous merits compared with ZnCo2O4 and ZnCo2O4@PPy. The more outstanding electrochemical performance of ZnCo2O4@PPy/SA electrode with higher reversible capacity, more excellent long-term cycling stability and better rate capability can be attributed to the porous hollow structure and PPy/SA coating, which not only reduce the path length for Li+ ions but also accommodate the volume expansion. Such structured composite electrode may have great potential for the application in lithium-ion batteries.

Effects of solid polymer electrolyte coating on the composition and morphology of the solid electrolyte interphase on Sn anodes

In order to discuss the effect of polymer coating layer on the Sn anode, the composition and morphology of the solid electrolyte interphase (SEI) film on the surface of Sn and Sn@PEO anode materials have been investigated. Compared with the bare cycled Sn electrode, the SEI on the surface of cycled Sn@PEO electrode is thinner, smoother, and more stable. Therefore, the Sn@PEO nanoparticles can basically keep the original appearance during cycling. Based on the results obtained from X-ray photoelectron spectroscopy (XPS), the SEI formed on the Sn@PEO electrode is characterized by inorganic components (Li2CO3)-rich outer layer and organic components-rich inner which could make the SEI more stable and inhibit the electrolyte immerging into the active materials. In particular, the elastic ion-conductive polyethylene oxide (PEO) coating could increase the toughness of SEI and allow the SEI to endure the stress variation in repetitive lithium insertion and extraction process. As a result, the Sn@PEO electrodes show significantly better capacity retention than bare Sn electrodes. The findings can serve as the theoretical foundation for the design of lithium-ion battery electrode with high energy density and long cycle life.