Novel sulfur/polythiophene composites with core/shell structure composites were synthesized via an in situ chemical oxidative polymerization method with chloroform as a solvent, thiophene as a reagent, and iron chloride as an oxidant at 0 °C. Different ratios of the sulfur/polythiophene composites were characterized by elemental analysis, FTIR, XRD, SEM, TEM, and electrochemical methods. A suitable ratio for the composites was found to be 71.9% sulfur and 18.1% polythiophene as determined by CV and EIS results. Conductive polythiophene acts as a conducting additive and a porous adsorbing agent. It was uniformly coated onto the surface of the sulfur powder to form a core/shell structure, which effectively enhances the electrochemical performance and cycle life of the sulfur cells. The initial discharge capacity of the active material was 1119.3 mA h g−1, sulfur and the remaining capacity was 830.2 mA h g−1 sulfur after 80 cycles. After a rate test from 100 to 1600 mA g−1 sulfur, the cell remained at 811 mA h g−1 sulfur after 60 cycles when the current density returned to 100 mA g−1 sulfur. The sulfur utilization, the cycle life, and the rate performance of the S−PTh core/shell electrode in a lithium−sulfur battery improved significantly compared to that of the pure sulfur electrode. The pore and thickness of the shell affected the battery performance of the lithium ion diffusion channels.

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This letter reports on the investigation of a binder-free cathode material to be used in rechargeable aluminum batteries. This cathode is synthesized by directly depositing V2O5 on a Ni foam current collector. Rechargeable aluminum coin cells fabricated using the as-synthesized binder-free cathode delivered an initial discharge capacity of 239 mAh/g, which is much higher than that of batteries fabricated using a cathode composed of V2O5 nanowires and binder. An obvious discharge voltage plateau appeared at 0.6 V in the discharge curves of the Ni-V2O5 cathode, which is slightly higher than that of the V2O5 nanowire cathodes with common binders. This improvement is attributed to reduced electrochemical polarization.

Ni-rich materials are appealing to replace LiCoO as cathodes in Li-ion batteries due to their low cost and high capacity. However, there are also some disadvantages for Ni-rich cathode materials such as poor cycling and rate performance, especially under high voltage. Here, we demonstrate the effect of dual-conductive layers composed of LiPO and PPy for layered Ni-rich cathode material. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy show that the coating layers are composed of LiPO and PPy. (NH)HPO transformed to LiPO after reacting with surface lithium residuals and formed an inhomogeneous coating layer which would remarkably improve the ionic conductivity of the cathode materials and reduce the generation of HF. The PPy layer could form a uniform film which can make up for the LiPO coating defects and enhance the electronic conductivity. The stretchy PPy capsule shell can reduce the generation of internal cracks by resisting the internal pressure as well. Thus, ionic and electronic conductivity, as well as surface structure stability have been enhanced after the modification. The electrochemistry tests show that the modified cathodes exhibited much improved cycling stability and rate capability. The capacity retention of the modified cathode material is 95.1% at 0.1 C after 50 cycles, whereas the bare sample is only 86%, and performs 159.7 mAh/g at 10 C compared with 125.7 mAh/g for the bare. This effective design strategy can be utilized to enhance the cycle stability and rate performance of other layered cathode materials.

Best of both worlds: A heterostructured material is synthesized that comprises a core of layered lithium-rich material and an outer layer of nanospinel material. This spinel/layered heterostructured material maximizes the inherent advantages of the 3D Li(+) insertion/extraction framework of the spinel structure and the high Li(+) storage capacity of the layered structure. The material exhibits super-high reversible capacities, outstanding rate capability and excellent cycling ability.