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Sodium‐ion batteries (SIBs) are postulated as sustainable energy storage devices for light electromobility and stationary applications. The anode of choice in SIBs is hard carbon (HC) due to its electrochemical performance. Among different HC precursors, bio‐waste resources have attracted significant attention due to their low‐cost, abundance, and sustainability. Many bio‐waste materials have been used as HC precursors, but they often require strong acids/bases for pre‐/post‐treatment for HC development. Here, the morphology, microstructure, and electrochemical performance of HCs synthesized from hazelnut shells subjected to different pre‐treatments (i. e., no pre‐treatment, acid treatment, and water washing) were compared. The impact on the electrochemical performance of sodium‐ion cells and the cost‐effectiveness were also investigated. The results revealed that hazelnut shell‐derived HCs produced via simple water washing outperformed those obtained via other processing methods in terms of electrochemical performance and cost–ecological effectiveness of a sodium‐ion battery pack. [ABSTRACT FROM AUTHOR]

To tackle the poor chemical/electrochemical stability of Li1+xAlxTi2‐x(PO4)3 (LATP) against Li and poor electrode|electrolyte interfacial contact, a thin poly[2,3‐bis(2,2,6,6‐tetramethylpiperidine‐N‐oxycarbonyl)norbornene] (PTNB) protection layer is applied with a small amount of ionic liquid electrolyte (ILE). This enables study of the impact of ILEs with modulated composition, such as 0.3 lithium bis(fluoromethanesulfonyl)imide (LiFSI)‐0.7 N‐butyl‐N‐methylpyrrolidinium bis(fluoromethanesulfonyl)imide (Pyr14FSI) and 0.3 LiFSI‐0.35 Pyr14FSI‐0.35 N‐butyl‐N‐methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI), on the interfacial stability of PTNB@Li||PTNB@Li and PTNB@Li||LiNi0.8Co0.1Mn0.1O2 cells. The addition of Pyr14TFSI leads to better thermal and electrochemical stability. Furthermore, Pyr14TFSI facilitates the formation of a more stable Li|hybrid electrolyte interface, as verified by the absence of lithium "pitting corrosion islands" and fibrous dendrites, leading to a substantially extended lithium stripping‐plating cycling lifetime (>900 h). Even after 500 cycles (0.5C), PTNB@Li||LiNi0.8Co0.1Mn0.1O2 cells achieve an impressive capacity retention of 89.1 % and an average Coulombic efficiency of 98.6 %. These findings reveal a feasible strategy to enhance the interfacial stability between Li and LATP by selectively mixing different ionic liquids. [ABSTRACT FROM AUTHOR]

Enabling green fabrication processes for energy storage devices is becoming a key aspect in order to achieve a sustainable fabrication cycle. Here, the focus was on the exploitation of the tragacanth gum, an exudated gum like arabic and karaya gums, as green binder for the preparation of carbon‐based materials for electrochemical capacitors. The electrochemical performance of tragacanth (TRGC)‐based electrodes was thoroughly investigated and compared with another water‐soluble binder largely used in this field, sodium‐carboxymethyl cellulose (CMC). Apart from the higher sustainability both in production and processing, TRGC exhibited a lower impact on the obstruction of pores in the final active material film with respect to CMC, allowing for more available surface area. This directly impacted the electrochemical performance, resulting in a higher specific capacitance and better rate capability. Moreover, the TRGC‐based supercapacitor showed a superior thermal stability compared with CMC, with a capacity retention of about 80 % after 10000 cycles at 70 °C. [ABSTRACT FROM AUTHOR]

Conversion/alloying materials (CAMs) are a potential alternative to graphite as Li‐ion anodes, especially for high‐power performance. The so far most investigated CAM is carbon‐coated Zn0.9Fe0.1O, which provides very high specific capacity of more than 900 mAh g−1 and good rate capability. Especially for the latter the optimal particle size is in the nanometer regime. However, this leads to limited electrode packing densities and safety issues in large‐scale handling and processing. Herein, a new synthesis route including three spray‐drying steps that results in the formation of microsized, spherical secondary particles is reported. The resulting particles with sizes of 10–15 μm are composed of carbon‐coated Zn0.9Fe0.1O nanocrystals with an average diameter of approximately 30–40 nm. The carbon coating ensures fast electron transport in the secondary particles and, thus, high rate capability of the resulting electrodes. Coupling partially prelithiated, carbon‐coated Zn0.9Fe0.1O anodes with LiNi0.5Mn1.5O4 cathodes results in cobalt‐free Li‐ion cells delivering a specific energy of up to 284 Wh kg−1 (at 1 C rate) and power of 1105 W kg−1 (at 3 C) with remarkable energy efficiency (>93 % at 1 C and 91.8 % at 3 C). [ABSTRACT FROM AUTHOR]

The use of water‐soluble, abundant biopolymers as binders for lithium‐ion positive electrodes is explored because it represents a great step forward towards environmentally benign battery processing. However, to date, most studies that employ, for instance, carboxymethyl cellulose (CMC) as a binder have focused on rather low electrode areal loadings with limited relevance for industrial needs. This study concerns the use of natural guar gum (GG) as a binding agent for cobalt‐free, high‐voltage LiNi0.5Mn1.5O4 (LNMO), which realizes electrodes with substantially increased areal loadings, low binder content, and greatly enhanced cycling stability. Co‐crosslinking GG through citric acid with CMC allows for an enhanced rate capability and essentially maintains the beneficial impact of using GG as a binder rather than CMC only. Lithium‐ion full cells based on water‐processed LNMO and graphite electrodes provide a remarkably high cycling stability with 80 % capacity retention after 1000 cycles at 1 C. [ABSTRACT FROM AUTHOR]

Manganese hexacyanoferrate (MnHCF) is made of earth‐abundant elements by a safe and easy synthesis. The material features a higher specific capacity at a higher potential than other Prussian blue analogs. However, the effect of hydration is critical to determine the electrochemical performance as both the electrochemical behavior and the reaction dynamics are affected by interstitial/structural water and adsorbed water. In this study, the electrochemical activity of MnHCF is investigated by varying the interstitial ion content through a joint operando X‐ray absorption spectroscopy and chemometric approach, with the intent to assess the structural and electronic modifications that occur during Na release and Li insertion, as well as the overall dynamic evolution of the system. In MnHCF, both the Fe and Mn centers are electrochemically active and undergo reversible oxidation during the interstitial ion extraction (Fe2+/Fe3+ and Mn2+/Mn3+). The adsorption of water results in irreversible capacity during charge but only on the Fe site, which is suggested by our chemometric analysis. The local environment of Mn experiences a substantial yet reversible Jahn–Teller effect upon interstitial ion removal because of the formation of trivalent Mn, which is associated with a decrease of the equatorial Mn−N bond lengths by 10 %. [ABSTRACT FROM AUTHOR]

Aluminum is an appealing anode material for high‐energy‐density lithium‐ion batteries (LIBs), owing to its low cost, environmental benignity, high specific capacity, and lower relative volume expansion compared with other alloying materials. However, both, the working and capacity fading processes are not yet consistently and comprehensively understood, which has largely hindered its development. In this study, the electrochemical alloying process of aluminum anodes with lithium is systematically studied by the combination of several in situ and ex situ techniques, providing new insights into phase transitions, electrode dynamics, and surface chemistry. Particular attention is paid to the role of the Li‐rich alloys (Li1+xAl). Its existence on the surface of the Al electrode is unexpectedly observed, and its growth in the electrode bulk is found to be strictly correlated with cell failure. Interestingly, cell failure can be delayed by choosing an appropriate electrolyte. This work contributes to a solid and comprehensive understanding of the puzzling Al (de‐)lithiation processes, which is fundamental and highly enlightening for future research work on Al and other alloyed anodes. [ABSTRACT FROM AUTHOR]

Aluminum, a cost‐effective and abundant metal capable of alloying with Li up to around 1000 mAh g−1, is a very appealing anode material for high energy density lithium‐ion batteries (LIBs). However, despite repeated efforts in the past three decades, reports presenting stable cycling performance are extremely rare. This study concerns recent findings on the highly reversible (de)lithiation of a micro‐sized Al anode (m‐Al) by using bis(fluorosulfonyl)imide (FSI)‐based electrolytes. By using this kind of electrolyte, m‐Al can deliver a specific capacity over 900 mAh g−1 and superior Coulombic efficiency (96.8 %) to traditional carbonate‐ and glyme‐based electrolytes (87.8 % and 88.1 %, respectively), which represents the best performance ever obtained for an Al anode without sophisticated structure design. The significantly improved electrochemical performance, which paves the way to realizing high‐performance Al‐based high energy density LIBs, can be attributed the peculiar solid–electrolyte interphase (SEI) formed by the FSI‐containing electrolyte. A better electrolyte for Al anode: This study concerns recent findings on the highly reversible (de)lithiation of a micro‐sized Al anode (m‐Al) by using bis(fluorosulfonyl)imide‐based electrolytes. By using this kind of electrolyte, m‐Al can deliver a specific capacity over 900 mAh g−1 and superior Coulombic efficiency (96.8 %) to traditional electrolytes. The significantly improved electrochemical performance is attributed to the peculiar solid–electrolyte interphase (SEI). [ABSTRACT FROM AUTHOR]

Abstract: Aqueous Na‐ion batteries may offer a solution to the cost and safety issues of high‐energy batteries. However, substantial challenges remain in the development of electrode materials and electrolytes enabling high performance and long cycle life. Herein, we report the characterization of a symmetric Na‐ion battery with a NASICON‐type Na2VTi(PO4)3 electrode material in conventional aqueous and “water‐in‐salt” electrolytes. Extremely stable cycling performance for 1000 cycles at a high rate (20 C) is found with the highly concentrated aqueous electrolytes owing to the formation of a resistive but protective interphase between the electrode and electrolyte. These results provide important insight for the development of aqueous Na‐ion batteries with stable long‐term cycling performance for large‐scale energy storage. [ABSTRACT FROM AUTHOR]

Abstract: Increasing the environmental benignity of lithium‐ion batteries is one of the greatest challenges for their large‐scale deployment. Toward this end, we present herein a strategy to enable the aqueous processing of high‐voltage LiNi0.5Mn1.5O4 (LNMO) cathodes, which are considered highly, if not the most, promising for the realization of cobalt‐free next‐generation lithium‐ion cathodes. Combining the addition of phosphoric acid with the cross‐linking of sodium carboxymethyl cellulose by means of citric acid, aqueously processed electrodes with excellent performance are produced. The combined approach offers synergistic benefits, resulting in stable cycling performance and excellent coulombic efficiency (98.96 %) in lithium‐metal cells. Remarkably, this approach can be easily incorporated into standard electrode preparation processes with no additional processing step. [ABSTRACT FROM AUTHOR]

Abstract: The room‐temperature molten salt mixture of N,N‐diethyl‐N‐(2‐methoxyethyl)‐N‐methylammonium bis(trifluoromethanesulfonyl) imide ([DEME][TFSI]) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is herein reported as electrolyte for application in Li–O2 batteries. The [DEME][TFSI]–LiTFSI solution is studied in terms of ionic conductivity, viscosity, electrochemical stability, and compatibility with lithium metal at 30 °C, 40 °C, and 60 °C. The electrolyte shows suitable properties for application in Li–O2 battery, allowing a reversible, low‐polarization discharge–charge performance with a capacity of about 13 Ah g - 1 carbon in the positive electrode and coulombic efficiency approaching 100 %. The reversibility of the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) is demonstrated by ex situ XRD and SEM studies. Furthermore, the study of the cycling behavior of the Li–O2 cell using the [DEME][TFSI]‐LiTFSI electrolyte at increasing temperatures (from 30 to 60 °C) evidences enhanced energy efficiency together with morphology changes of the deposited species at the working electrode. In addition, the use of carbon‐coated Zn0.9Fe0.1O (TMO‐C) lithium‐conversion anode in an ionic‐liquid‐based Li‐ion/oxygen configuration is preliminarily demonstrated. [ABSTRACT FROM AUTHOR]

The performance of graphite//LiNi0.5Mn1.5O4 (LNMO) cells, both electrodes of which are made using water-soluble sodium carboxymethyl cellulose (CMC) binder, is reported for the first time. The full cell performed outstandingly over 400 cycles in the conventional electrolyte ethylene carbonate/dimethyl carbonate-1 m LiPF6, and the delivered specific energy at the 100th, 200th, 300th, and 400th cycle corresponded to 82, 78, 73, and 66 %, respectively, of the initial energy value of 259 Wh kg−1 (referring to the sum of the two electrode-composite weights). The good stability of high-voltage, LNMO-CMC-based electrodes upon long-term cycling is discussed and the results are compared to those of LNMO-composite electrodes with polyvinylidene fluoride (PVdF). LNMO-CMC electrodes outperformed those with PVdF binder, displaying a capacity retention of 83 % compared to 62 % for the PVdF-based electrodes after 400 cycles at 1 C. CMC promotes a more compact and stable electrode surface than PVdF; undesired interfacial reactions at high operating voltages are mitigated, and the thickness of the passivation layer on the LNMO surface is reduced, thereby enhancing its cycling stability. [ABSTRACT FROM AUTHOR]