This study presents a low-cost, one-step electrode patterning method that uses a template with micropillars to indent a hexagonal array of channels in high-loading graphite anodes for faster electrolyte infiltration and Li-ion transport. In contrast to prior studies on using laser micro-machining, active material losses could be completely avoided by the proposed methodology. The process can also be made roll-to-roll and continuous. Furthermore, the very small volume fraction of the introduced channels (<1wt.%) has little impact on practically attainable energy density or specific energy. Yet, thus introducing pore channels significantly reduces electrolyte infiltration time and improves rate performance.
The complex growth behavior of lithium (Li) metal has posed significant challenges in gaining an understanding of the operational mechanisms of lithium batteries. The intricate composition and structure of the solid electrolyte interphase (SEI) have added layers of difficulty in characterizing the dynamic and intricate electrochemical processes involved in lithium metal anodes. Real-time observation of Li metal growth has particularly been challenging. Fortunately, atomic force microscopy (AFM) has emerged as a powerful tool, offering invaluable in situ and nanoscale insights into the interface. Its unique contact detection method, remarkably high Z sensitivity, diverse operating modes, and ability for real-time detection during battery operation make AFM a crucial asset. This review aims to comprehensively explore recent advances in AFM application for studying lithium battery anodes. It particularly focuses on examining the formation process and various properties of the solid electrolyte interphase in lithium batteries. In addition, here, we consolidate and evaluate the existing literature pertaining to AFMbased research on the nucleation, deposition, and stripping processes of lithium metal. The objective is to highlight the growth mechanism of lithium metal and elucidate the factors influencing its growth.
Sodium-ion batteries are emerging as promising alternative energy sources compared to lithium-ion batteries, due to the abundant sodium resources in Earth’s crust and their low cost. Nevertheless, the larger ionic radius of sodium ions leads to minor energy density in sodium-layered oxide cathodes. To address this, anionic redox has attracted significant attention as it provides additional capacity beyond cationic redox. In this comprehensive review, the history and fundamental mechanisms of anionic redox are systematically summarized, and the recent advancements in sodium-layered oxides with anionic redox is categorized and discussed according to deficient sodiumlayered oxides, stoichiometric sodium-layered oxides, and sodium-rich layered oxides. Finally, several prospects and challenges for anionic redox-layered oxide cathodes have also been proposed. This review sheds light on the potential trajectory of sodium-ion battery technology and highlights the pathways to harness the full capabilities of anionic redox for energy storage applications.
Ideally, once batteries reach their end-of-life, they are expected to be collected, dismantled, and converted into black mass (BM), which contains significant amounts of valuable metals. BM can be regarded as a sort of urban mine, where recyclers extract and reintroduce the materials into new battery manufacturing. Focusing on BM, this article discusses the necessity of BM recovery and current recycling situations. Although the benefits of recycling are widely acknowledged, many challenges and issues remain. The BM market is still in its infancy and relevant regulatory frameworks need to be updated with respect to the widespread use and advancement of lithium-ion batteries. Current BM producing and processing technologies are gaining momentum and still have room for large improvements in terms of economic feasibility and environmental footprint. Finding solutions for these challenges in the end requires efforts from both researchers and industrial stakeholders with growing interests and long-term patient engagement. Battery regulations and legal support are highly anticipated for industries to keep high levels of commitment to long-term investments.
Cu(OH)2 has the advantages of ease of structural regulation, good conductivity, and relatively low cost, making it a suitable candidate material for use as an electrocatalyst. However, its catalytic efficiency and stability still need to be improved further. Therefore, Cu(OH)2/Cu2S was successfully prepared on copper foam (CF) using the in situ growth and hydrothermal method. The structural characterization showed that sulfidation treatment induced transformation of Cu(OH)2/CF from smooth nanorods into a corallike structure, which exposed more active sites of Cu(OH)2/Cu2S and enhanced the performance of electrocatalytic hydrogen evolution reaction (HER). Compared with Cu(OH)2, Cu(OH)2/Cu2S showed better alkaline HER performance, especially when the vulcanization concentration was 0.1 M, the overpotential of Cu(OH)2/Cu2S was 174 mV, and the reaction kinetics was 64 mv dec−1 at a current density of 10mA cm−2. In this work, the morphology and electronic structure of copper-based metal sulfide electrocatalysts were adjusted by sulfide treatment, which provided a new reference for improving HER performance.
All-solid-state lithium (Li) metal batteries combine high power density with robust security, making them one of the strong competitors for the next generation of battery technology. By replacing the flammable and volatile electrolytes commonly found in traditional Li-ion batteries (LIBs) with noncombustible solid-state electrolytes (SSEs), we have the potential to fundamentally enhance safety measures. Concurrently, SSE would be capable of fitting high specific capacity (3860 mAh g-1) metal Li and is expected to break through the upper limit of mass-energy density (350 Wh kg-1) of existing LIBs system. Nevertheless, the growth of Li dendrites on the negative side or the nucleation of Li inside SSEs may give rise to battery short circuits, which is the primary factor limiting the application of Li metal. Recognizing this, the focus of this review is to provide a perspective for experimentalists and theorists who closely monitor various surface/interface and microstructure phenomena to understand Li dendrites. The strategies to reveal the complicated deposition mechanism and to control the dendrite growth of metal Li in solid-state batteries, as well as the advanced characterization methods of metal Li, provide suggestions for the practical research of solid-state Li metal batteries.
Lithium-ion batteries suffer from severe capacity loss and even fail to work under subzero temperatures, which is mainly due to the sluggish Li+ transportation in the solid electrolyte interphase (SEI) and desolvation process. Ethyl acetate (EA) is a highly promising solvent for lowtemperature electrolytes, yet it has poor compatibility with graphite (Gr) anode. Here, we tuned the interfacial chemistry of EA-based electrolytes via synergies of anions. ODFB− with low solvation numbers, participates in the solvation sheath, significantly reducing the desolvation energy. Meanwhile, combined with the high dissociation of FSI−, the reduction of both anions constructs an inorganic-rich SEI to improve interfacial stability. The electrolyte enables Gr anode to deliver a capacity of 293 mA h g−1 and 2.5 Ah LiFePO4∥Gr pouch cell to exhibit 96.85% capacity retention at −20°C. Remarkably, LiFePO4∥Gr pouch cell with the designed electrolyte can still retain 66.28% of its room-temperature capacity even at −40°C.
High energy density Ni-rich layered oxide cathodes LiNi0.83Co0.12Mn0.05–xAlxO2 (x = 0 [NMC], 0.025 [NMCA], 0.05 [NCA]) are fabricated in two different microstructural forms: (i) nanoparticles (NP) and (ii) nanofibers (NF), to evaluate the morphology and compositional effect on the electrochemical properties using same precursors, with the latter fabricated by electrospinning process. Although all the cathodes exhibit a similar crystal structure as confirmed using X-ray diffraction and Raman spectroscopy, the contrasting difference is observed in their electrochemical properties. XRD and XPS analyses indicate a higher amount of cationic disorder for the NP cathodes compared to their NF counterparts. Nanofibrous Ni-rich layered oxide cathodes exhibit higher discharge capacities at all C-rates in comparison to NP cathodes. When cycled at 1C-rate for 100 cycles, capacity retention of 81% is observed for NCA-NF, which is superior to all cathodes. Voltage decay as a function of the charge-discharge cycle is found to be low (0.2mV/cycle) for nanofibrous cathodes compared to 1.5mV/cycle for NP cathodes. The good rate capability and cyclic stability of nanofibrous Ni-rich layered oxide cathodes are attributed to a shorter pathway of Li+ diffusion and a large proportion of the active surface area.
Graphite is one of the most widely used anode materials in lithium-ion batteries (LIBs). The recycling of spent graphite (SG) from spent LIBs has attracted less attention due to its limited value, complicated contaminations, and unrestored structure. In this study, a remediation and regeneration process with combined hydrothermal calcination was proposed to remove different impurities as value-added resources from SG. This study focuses on the application of different removal methods for different impurity metals by hydrothermal and acid leaching under different conditions for the removal of Cu, Li, Co, Mn, and Ni from SG. Then, mild-tempreture calcination of SG was performed to remove residual organic compounds. The regenerated graphite (RG) was found to have a better morphology structure and increased pore volume, which is more favorable for the embedding and desorption of lithium (Li) in graphite. In terms of electrochemical performance, the first dischargespecific capacity of RG at 0.5 C is 359.40 mAh/g, with a retention of 353.49 mAh/g after 100 cycles (retention rate of 98.36%). This study can be a green and efficient candidate for the regeneration of graphite from spent lithium-ion batteries as anode material by reduced restoration temperature, with different metal resources as by-products.
Silicon (Si) has emerged as a promising anode material in the pursuit of higher energy-density lithium-ion batteries (LIBs). The large-scale applications of Si anode, however, are hindered by its significant swelling, severe pulverization, and continuous electrode-electrolyte reaction. Therefore, the development of an efficient approach to mitigate Si particle swelling and minimize interface parasitic reactions has emerged as a prominent research focus in both academia and industry. Here, a facile and scalable strategy is reported for the preparation of a double-layer coated submicron Si anode, comprising ceramic (silicon oxide) and graphene layers, denoted as Si@SiOx@G. In this approach, SiOx is in situ synthesized on the surface of Si and bonded with graphene through hydrogen bond interactions. The prepared Si electrode shows exceptional structural integration and demonstrates outstanding electrochemical stability, with a capacity retention of 92.58% after 540 cycles at 1 A g−1, as well as remarkable rate capability, achieving a specific capacity of 875 mAh g−1 at 2 A g−1. This study presents a straightforward yet pragmatic approach for the widespread implementation of high-energy-density siliconbased batteries.