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Abstract This work investigates the application of poly(3,4‐ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) with polyethylene oxide (PEO) in lithium batteries (LIBs). This composite film comprising PEDOT:PSS and PEO was 3D printed onto a carbon nanofiber (CNF) substrate to serve as a layer between the polypropylene (PP) separator and the lithium anode in LIBs. The resulting CNF‐PEDOT:PSS‐PEO film exhibited superior mechanical and thermal properties compared to conventional PP separators. Mechanical tests revealed a high Young's modulus and puncture strength for the composite film. Thermal stability tests indicated that the CNF‐PEDOT:PSS‐PEO film remained stable at higher temperatures compared to the commercial PP separator, and combustion tests confirmed its superior fire‐resistance properties. In terms of conductivity, the composite film maintained comparable ionic conductivity to the commercial PP separator. Electrochemical tests demonstrated that LIBs incorporating the CNF‐PEDOT:PSS‐PEO film exhibited slight improvement in cycling performance, with a 7.9 % increase in long‐term cycling capacity compared to LIBs using only the commercial PP separator. These findings indicate that the developed CNF‐PEDOT:PSS‐PEO composite film holds promise to improve safety, while maintaining the electrochemical performance of LIBs by reducing dendrite formation and enhancing thermal stability. 

High-entropy materials (HEMs) constitute a revolutionary class of materials that have garnered significant attention in the field of materials science, exhibiting extraordinary properties in the realm of energy storage. These equimolar multielemental compounds have demonstrated increased charge capacities, enhanced ionic conductivities, and a prolonged cycle life, attributed to their structural stability. In the anode, transitioning from the traditional graphite (372 mAh g−1) to an HEM anode can increase capacity and enhance cycling stability. For cathodes, lithium iron phosphate (LFP) and nickel manganese cobalt (NMC) can be replaced with new cathodes made from HEMs, leading to greater energy storage. HEMs play a significant role in electrolytes, where they can be utilized as solid electrolytes, such as in ceramics and polymers, or as new high-entropy liquid electrolytes, resulting in longer cycling life, higher ionic conductivities, and stability over wide temperature ranges. The incorporation of HEMs in metal–air batteries offers methods to mitigate the formation of unwanted byproducts, such as Zn(OH)4 and Li2CO3, when used with atmospheric air, resulting in improved cycling life and electrochemical stability. This review examines the basic characteristics of HEMs, with a focus on the various applications of HEMs for use as different components in lithium-ion batteries. The electrochemical performance of these materials is examined, highlighting improvements such as specific capacity, stability, and a longer cycle life. The utilization of HEMs in new anodes, cathodes, separators, and electrolytes offers a promising path towards future energy storage solutions with higher energy densities, improved safety, and a longer cycling life. 

Dendritic growth of lithium (Li) is hindering potential applications of Li-metal batteries, and new approaches are needed to address this challenge. The confinement effect of two-dimensional materials triggered by strong molecular interactions between parallelly-aligned graphene oxide (GO) at Li metal interface is proposed here as a new strategy to suppress the dendritic growth of Li. The effectiveness of aligned GO for Li-metal cells is shown for two different polymer separator cells:liquid electrolytes with porous propylene (PP) separators and solid polyethylene oxide (PEO) electrolytes. For the case of liquid electrolytes, PP separators were modified with plasma treatment to induce the alignment of GO layers. The Li‖Li cells with aligned GO illustrate a stable Li platting/stripping (up to 1000 cycles). The Li‖lithium iron phosphate (LFP) battery cells with aligned GO could cycle at 5C for 1000 cycles (∼90% capacity retention). For solid polymer electrolyte (SPE) cells, GO–Li confinement effect is also effective in Li dendrites suppression enhancing the stability and lifespan of Li-metal batteries. The Li‖LFP cell with the GO-modified SPE showed ∼85% capacity retention after 200 cycles at 1C. Such combined high rate capability and number of cycles exceeds the previously reported performances for both liquid and SPE-based Li‖LFP cells. This points to a new opportunity for utilizing the confinement effect of two-dimensional materials for the development of next generation, fast rate rechargeable Li batteries.