Boric acid (BA) was employed as a sintering aid to tailor the microstructure of high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) synthesized by a solid-state route. BA additions of 0.5-1.0 mol% yielded smoother micrometer-scale particles and slight lattice contraction while maintaining the spinel phase, whereas 5.0 mol% led to over-coarsening and reduced crystallinity. First-cycle irreversibility was minimized near 1.0 mol% BA due to a reduced cathode-electrolyte interfacial area. Under 60 degrees C cycling, the 1.0 mol% BA sample delivered 92.1 mAh g_ 1 These results indicate that appropriate BA addition can balance capacity dilution and interfacial stabilization, thereby enhancing the high-temperature durability of LNMO positive electrodes. at the 80th cycle with 88.2 % retention, outperforming BA-free and other BA-containing LNMO electrodes.

Transition metal oxides that store lithium through a conversion reaction accommodate lithium ions and electrons during charge-discharge cycles, reducing the transition metal to its metallic state. Meanwhile, oxygen combines with lithium to form lithium oxide (Li2O). Although this mechanism offers a high theoretical capacity, it presents several challenges. Strong bonding between transition metals and oxygen induces voltage hysteresis during cycling, resulting in a high overpotential. Furthermore, substantial volume changes during cycling adversely affect long-term stability. To address these issues, this study explored the potential of Mn SiO , synthesized via a solidstate reaction method, as a negative electrode material for lithium-ion batteries. Mn SiO was prepared using MnCO and SiO as precursors and heat-treated at 1000 C under an argon atmosphere, yielding a high-purity material. We aim to evaluate and enhance the electrochemical performance of this material, particularly through its combination with carbon, to offer a novel and effective strategy for high-density energy storage. Notably, incorporating carbon into Mn SiO-based composites significantly improved performance, including electrical conductivity, and mitigated volume expansion, resulting in improved cycling stability and rate capability. The utility of carbon in this composite provides a novel direction for maximizing the potential of combined electrochemical storage systems. These findings indicate that Mn SiO4 has the potential to be used as a negative electrode material in high-capacity lithium-ion batteries and that carbon compositing is a promising strategy for enhancing the electrochemical properties of Mn SiO-based negative electrodes.

Lithium-ion batteries (LIBs) play a crucial role in various fields, including electronic devices and electric vehicles, due to their high energy density. Ni-based layered materials such as LiNi(0.6)Co(0.2)M(0.2)nO(2) (NCM622) have been predominantly used as positive electrodes to achieve high energy density. However, there is a growing demand to enhance cost efficiency and safety. As a result, interest in phosphate-based active materials, such as LiMn0.6Fe0.4PO4 (LMFP64), which use Fe and Mn, has been increasing. In this study, the electrodes with various blending ratios of NCM622 and LMFP64 were fabricated, and their physical and electrochemical properties were evaluated. For these two complementary positive electrode materials, the maximum density was achieved when a small amount of LMFP64 was blended with NCM622. However, the electrochemical properties were found to vary linearly with the blending ratio, reflecting the inherent characteristics of the two active materials. Electrochemical analysis showed that electrodes using NCM622 alone exhibited the best capacity and rate capability. As the blending ratio of LMFP64 increased, these electrochemical performance metrics decreased linearly. Therefore, by adopting blended electrodes composed of NCM622 and LMFP64, it is expected that optimized electrodes with desired properties can be developed.

The lithium iron phosphate (LiFePO4; LFP) cathode is gaining prominence owing to its exceptional electrochemical performance, thermal stability, and cost-effectiveness. The properties of the iron phosphate precursor considerably influence the performance of the LFP cathode. Consequently, we established that a microcrystallization process under varied pH conditions leads to a smaller, more uniform and highly crystalline precursor of FePO42H2O, in contrast to the amorphous FePO4xH2O obtained prior to microcrystallization. This microcrystallization process also effectively removes undesired impurities that lead to metallic iron in the LFP cathode. Notably, LFP synthesized using a precursor microcrystallized at pH 2.6 shows superior physicochemical properties, including higher crystallinity, reduced lattice defects, and improved cycling stability and rate capability. These findings demonstrate that microcrystallizing FePO4xH2O into FePO42H2O under controlled pH and temperature conditions effectively improves the crystal structure of LFP, thereby contributing to enhanced electrochemical performance for advanced Li-ion batteries.

We have developed a versatile mathematical framework integrated with an automated reactor system to design and reify highly customizable full concentration gradient (FCG) in high-nickel cathodes for advanced Li-ion batteries. This method provides precise and independent control of the average composition, slope, and curvature of FCGs, enabling the optimization of structural and mechanical properties of the cathode materials. We have showcased this method with Ni0.8Co0.1Mn0.1(OH)2 precursors of controlled FCGs, which unlocked an optimized cathode with excellent cycling stability without crack formation after repeated cycles. This work opens up new possibilities for the design and manufacturing of advanced cathode materials, enabling safer, high-performance batteries.

Silicon monoxide (SiO) is a high-capacity alloy-type negative electrode material for lithium-ion batteries, but it suffers from severe volume expansion and low electrical conductivity. Conventional carbon coating by chemical vapor deposition improves conductivity but requires high temperatures (> 700 °C) that trigger disproportionation reactions, leading to the formation of large Si crystallites and accelerated degradation. Here, electroless nickel (Ni) plating is employed as a low-temperature approach to enhance the conductivity of SiO without structural damage. SiO particles were sensitized with SnCl2, activated with PdCl2, and coated with Ni via sodium hypophosphite reduction at 50 °C and 80 °C. A higher plating temperature resulted in greater Ni loading and significantly improved cycling stability. These results demonstrate that electroless Ni plating is a thermally benign and effective strategy for advancing the performance of SiO-based negative electrodes.

MnO is a negative electrode material that has significant potential for application in high-capacity Li-ion batteries because of its low material cost and the fact that its conversion reaction allows excellent Li storage capability (756 mAh g-1). However, despite its high theoretical capacity, the practical application of MnO is impeded by its low conductivity and the significant volume changes exhibited by the material during lithiation/delithiation. Herein, we report a simple, solvent-free method for synthesizing surface-nitrided MnO by heating a homogeneous mixture of MnO powder and urea in an auto- genic reactor. The nitrided layer formed on the surface of the microsized MnO particles acts as a buffer, mitigating volume changes during lithiation and delithiation, and its high conductivity reduces the charge-transfer resistance of MnO. These enhanced properties collectively serve to optimize the electrochemical performance of MnO electrodes. In Li/MnO cell tests (for a 50.0 wt% urea sample), the MnO surface is converted into electrochemically inert Mn N during synthesis. It exhibits a slight reduction in reversible capacity but demonstrates significantly improved cyclability and rate capability when compared to bare MnO. This improvement is attributed to the ability of the nitrided layer to stabilize the electrode structure and facilitate more efficient charge transfer. We expect the results of this study to provide insights into simple surface-coating methods and facilitate the application of conversion-type anode materials (such as MnO) in high-capacity Li-ion batteries.

Research on silicon monoxide (SiO) negative electrode materials for lithium-ion batteries has been actively pursued to enhance performance. In this study, we aimed to improve electrochemical performance by optimizing the electron transport pathways. The content of carbon black, as a conducting agent, was adjusted to vary the number of electron transport channels, and the resulting performance was compared. Additionally, two strategies were adopted. First, a 3D porous Cu foam was used as the current collector instead of flat Cu foil to provide macroscopic electron transport pathways. Second, a portion of carbon black was replaced with carbon nanotubes (CNTs) to develop microscopic electron transport pathways. These modifications were applied individually and simultaneously to fabricate and evaluate the electrodes. The results showed that increasing the carbon black content led to more electron transport channels, improving cycle performance and rate capability. Furthermore, the use of Cu foam and CNTs further enhanced performance. These findings demonstrate the establishment of efficient electron transport pathways without increasing the content of conductive additives, which could contribute to the commercialization potential of high-capacity negative electrodes in the future.

The effects of binder composition on natural graphite (NG)/carbon-coated silicon monoxide (c-SiO) composite electrodes were investigated by varying the ratio of sodium carboxymethyl cellulose (CMC) to styrene-butadiene rubber (SBR). A higher CMC content improved cycling stability, rate capability, and reduced resistance, but also increased electrode brittleness. In contrast, a higher SBR fraction enhanced mechanical flexibility but compromised electrochemical stability. Electrode resistivity and GITT analyses confirmed that CMC promotes strong interfacial adhesion and well-established electron transport pathways. Overall, the results demonstrate a clear trade-off between electrochemical performance and mechanical durability and suggest that a balanced SBR/CMC ratio provides the most reliable route for practical NG/c-SiO composite negative electrodes.

As lithium-ion battery (LIB) use rises, recycling becomes imperative. Efficiently overdischarging LIBs for residual energy extraction is crucial for safe recycling. Our study analyzes the electrochemical behavior during overdischarge for positive electrode materials, including LiNi0.6Co0.2Mn0.2O2 (NCM622), LiNi0.8Co0.1Mn0.1O2 (NCM811), LiFePO4 (LFP), LiCoO2 (LCO), and LiMn2O4 (LMO). Electrochemical evaluations involve half cells and full cells subjected to constant current overdischarge beyond normal operating ranges. In positive electrode half-cells, a material-dependent conversion reaction was observed, while full cells exhibited similar behaviors during overdischarge to 0 V due to increasing voltage at the negative electrode. Distinct electrochemical variations emerged under forced discharge below 0 V, particularly in the NCM series, showing a gradual voltage decrease to −2 V followed by an internal short circuit. In contrast, LFP, LCO, and LMO swiftly stabilized near 0 V, attributed to the lower initial Coulombic efficiency of NCM materials leading to an early rise in negative electrode potential. To recycle used lithium-ion batteries (LIBs), it’s crucial to optimize conditions that ensure both efficient and safe overdischarge, considering the characteristics of positive electrode materials.

Among the electrode manufacturing processes for lithium-ion batteries, the drying process is crucial for production speed and process cost. Particularly, as the loading level of the electrode increases to enhance the energy density of the battery, optimizing process conditions for electrode drying becomes more critical. In this study, we compared the drying time and electrochemical performance of the positive electrode prepared at different drying temperatures. LiNi0.6Co0.2Mn0.2O2 (NCM622) was used as the active material and manufactured under various drying temperature conditions ranging from 120 degrees C to 210 degrees C at loading levels of 2.5 and 4.5 mAh cm(-2). The physical and electrochemical properties of the electrodes were compared. As the loading level of the electrode increases, the drying time of the electrode also increases, but this time can be reduced by increasing the drying temperature. The drying temperature used in manufacturing the NCM622 positive electrode does not significantly affect the electrochemical performance but drying above 210 degrees C resulted in an increase in the volume resistivity of the electrode and a decrease in electrochemical performance. Accordingly, in the manufacture of high-loading electrodes, the drying temperature was increased to 190 degrees C to shorten the electrode manufacturing time without a loss of performance.

Lithium-ion batteries (LIBs) are used in various fields such as electronic devices and electric vehicles. The high energy density of LIBs has traditionally been a significant advantage. However, there is now an increasing demand for enhanced cost-effectiveness and safety. Phosphate-based positive electrode materials have been proposed as alternatives to Ni-based layered oxide materials. However, LiFePO4 is limited by its low operating voltage, leading to decreased energy density, while LiMnPO4 exhibits inadequate electrochemical performance. Consequently, there is increasing anticipation surrounding LMFP (LiMn1-xFexPO4), which leverages the benefits of combining Fe and Mn. LFMP offers the safety advantages of phosphate materials and the cost-effectiveness from the natural abundance of Fe and Mn, further enhanced by the complementary operating voltage and electrochemical activity derived from the Fe-Mn combination. In this study, we conducted different studies depending on electrode design and manufacturing process in order to improve LiMn0.6Fe0.4PO4 (LMFP64) performance. To comprehend the typical characteristics of the LMFP64 positive electrode, various electrodes with differing compositions and loading levels were fabricated. The physical properties of the fabricated electrode were assessed, alongside the evaluation and comparison of electrochemical properties, including cycle performance and rate capability. Subsequently, modifications to the electrode design were made to incorporate new components or additives with the aim of improving LMFP electrode performance. The electrode fabrication process was expanded to enhance the electrochemical performance of LMFP. Adjustments to the pore structure with electrode composition led to further performance improvements. Additionally, nano-sized LMFP powder was blended with commonly used micro-sized NCM-based active materials. Although the blending did not exhibit notable synergy, the higher electrode density was achieved than that of the individual electrodes and ensured the required electrode performance based on the properties of both active materials due to the appropriate mixing ratio. Thus, it becomes feasible to configure electrodes that align with user demands in terms of cost and performance, thereby diversifying the battery design.

Zinc anodes are expected as a promising alternative to lithium-based anodes in energy storage systems due to their low cost, high theoretical capacity, and environmental friendliness. However, the development of efficient and stable zinc anode requires a fundamental understanding of the interfacial processes occurring during zinc deposition and dissolution cycling. In this study, we employed electrochemical quartz crystal microbalance (EQCM) analysis to investigate the potential-dependent formation and decomposition of surface films on zinc metal anodes in sulfate-based aqueous electrolytes. Changes in frequency and motional resistance served as complementary descriptors, with motional resistance being a highly selective indicator for probing dynamic surface film formation driven by side reactions at the zinc anode. While the frequency change provided the overall changes in the mass of both zinc metal and surface films, changes in the motional resistance selectively reflected the amount and nature of the visco-elastic interface that comprise the surface films. The two descriptors provide quantitative and complementary means to discover the complex interfacial processes such as the formation of surface visco-elastic films, guiding to the development of more stable and efficient zinc-based electrochemical systems.

Given the critical importance of safety in lithium-ion batteries (LIBs), titanium dioxide (TiO 2 ) is widely regarded as a reliable material for the negative electrode.Anatase TiO 2 is a safe negative electrode material in LIBs, attributed to its high redox potential (1.5-1.8V vs. Li/Li + ), which exceeds that of commercially available graphite, alleviating the risk of lithium plating.In addition, TiO 2 has gained considerable attention as a cost-effective negative electrode material for LIBs, owing to its versatility in nano-sized forms.The use of nano-sized TiO 2 as an electrode-active material reduces the diffusion distance of Li + ions.However, TiO 2 is adversely affected by its inherently low electronic conductivity, which hinders its rate performance.Herein, we investigated the surface treatment of commercially available TiO 2 nanoparticles with anatase structure using a heat-treatment process in the presence of urea or thiourea.Our objective was to leverage the eco-friendly nitridation of TiO 2 from the thermal decomposition of urea or thiourea, enhancing their electrochemical performance in lithium-ion batteries while minimizing environmental impact.Specifically, we employed an autogenic reactor (AGR) in a closed space to ensure an adequate reaction between NH 3 and TiO 2 , preventing NH 3 from escaping into the external environment, as observed in open systems.Consequently, surface nitridation enhanced the overall electrochemical performance, including the rate capability, capacity retention, and initial Coulombic efficiency (ICE).Notably, a remarkable enhancement was observed for the thiourea-treated TiO 2 .Compared to the pristine TiO 2 , the thiourea-treated TiO 2 demonstrated a nearly threefold increase in capacity at 1.0 C and a nearly two-fold increase in capacity retention.

As the electric vehicle (EV) market continues to expand in efforts to reduce CO2 emissions, so does the market for lithium-ion batteries. However, instances of overcharging can occur due to battery management system (BMS) inaccuracies or voltage discrepancies among cells. Overcharging can result in structural collapse and transition metal elution due to excessive delithiation from the positive electrode. Additionally, issues such as lithium plating at the negative electrode and electrolyte decomposition due to side parasitic reactions can arise. These problems collectively compromise the cycle life of lithium-ion batteries (LIBs), emphasizing the importance of understanding the effects of overcharging on the internal components of the cell. It's widely understood that overcharging diminishes battery performance. This study aims to analyze the capacity degradation mechanism of cells when subjected to overcharging using coin-type full cells with LiNi0.6Co0.2Mn0.2O2 (NCM622) positive electrode and graphite negative electrode. The cells were cycled at a current of 0.1 C (170 mA/g for NCM622), with normal charging conditions (4.2 V), and subjected to overcharging at three voltage thresholds (4.35 V, 4.5 V, and 4.65 V). The analysis aimed to identify the causes of capacity degradation when the capacity dropped to 80% of its initial value. Three degradation models were employed for analysis: (i) loss of active material (LAM), involving the NCM material loss from structural collapse and elution; (ii) loss of lithium inventory (LLI), attributed to electrolyte decomposition from the irreversible reaction of lithium plating and solid electrolyte interphase (SEI) reformation; and (iii) polarization increase (PI), arising from factors such as film thickening or inadequate contact. The cell degradation mechanism was analyzed in two ways. The first method involved calculating the predicted full cell data using half cell data. Using the voltage profile at the beginning-of-life (BoL) of NCM622 and graphite half cells, the contributions of LAM, LLI, and PI were applied differently to each to simulate voltage profiles and derivative capacity plot (dQ/dV) profiles of a full cell with 20% capacity degradation at the end-of-life (EoL) to be similar. Through this simulated data, it was possible to quantitatively calculate the contribution of the degradation model according to each overcharged voltage. The second method involves using the dV/dQ and dQ/dV profiles of the full cell. The alteration in the shape of these profiles was interpreted as the capacity degradation. A comparison was made for each degree of degradation of the full cell regarding the size and shifted voltage of the peaks in the dV/dQ and dQ/dV profiles. To validate the degradation contributions derived from the failure model, degraded full cells were disassembled, and positive and negative electrodes were fabricated and tested independently as half cells with Li metal counter electrode. The results obtained were compared against those derived from the model, confirming the accuracy of the degradation model calculations. This study provided deeper insights into the capacity degradation modes based on the extent of overcharging.

The carbon-coated silicon monoxide (c-SiOx), which is a negative electrode active material for lithium-ion batteries (LIBs), has a limited cycle performance due to severe volume changes during cycles, despite its high specific capacity. In particular, the significant volume change of the active material can deform the electrode structure and easily damage the electron transfer pathway. To improve performance and mitigate electrode damage caused by volume changes, we replaced parts of the carbon black conducting agent with carbon nanotubes (CNTs) having a linear shape. The content of the entire conductive material in the electrode was fixed at 10% by mass, and the relative content of CNTs ranged from 0% to 25% by mass to prepare electrodes and evaluate electrochemical performance. As the CNT content in the electrode increased, both cycle life and rate capability improved. Even a small amount of CNT can significantly improve the electrochemical performance of a c-SiOx negative electrode with large volume changes. Furthermore, dispersing CNTs effectively can lead to achieving the equivalent performance with a reduced quantity of CNTs.

As the use of lithium-ion secondary batteries is rapidly increasing due to the rapid growth of the electric vehicle market, the disposal and recycling of spent batteries after use has been raised as a serious problem. Since stored energy must be removed in order to recycle the spent batteries, an effective discharging process is required. In this study, graphite and NCM622 were used as active materials to manufacture coin-type half cells and full cells, and the electrochemical behavior occurring during overdischarge was analyzed. When the positive and negative electrodes are overdischarged respectively using a half-cell, a conversion reaction in which transition metal oxide is reduced to metal occurs first in the positive electrode, and a side reaction in which Cu, the current collector, is corroded following decomposition of the SEI film occurs in the negative electrode. In addition, a side reaction during overdischarge is difficult to occur because a large polarization at the initial stage is required. When the full cell is overdischarged, the cell reaches 0 V and the overdischarge ends with almost no side reaction due to this large polarization. However, if the full cell whose capacity is degraded due to the cycle is overdischarged, corrosion of the Cu current collector occurs in the negative electrode. Therefore, cycled cell requires an appropriate treatment process because its electrochemical behavior during overdischarge is different from that of a fresh cell.

The Front Cover shows the generation of tailor-made pores by the electrochemical activation of expanded graphite for a magnesium−organocation hybrid battery. Under the electric field, the organocations expand the graphene layers like drilling vehicles that open the undersea tunnel with sufficient space for the following submarines, which symbolizes the same organocations that freely move to store and release electricity efficiently through the tailor-made pores that were generated by electrochemical activation. More information can be found in the Research Article type by S. K. Mohanty et al.

Persisting limitations of lithium-ion batteries (LIBs) in terms of safety, energy and power density, natural resources, and the price call for expeditious research to develop the "beyond Li-ion" technologies. In this regard, magnesium-organocation hybrid batteries (MOHB) hold the potential to address the above issues associated with LIBs by utilizing abundant and inexpensive elements of magnesium and carbon for the anode and cathode, respectively. Moreover, magnesium metal anode is highly energy-dense yet less susceptible to the dendrite formation, enabling safer operation compared to lithium metal anodes. In this study, we targeted to increase the capacity and rate capability of porous carbon cathode of MOHB by generating tailor-made pores, which were provided by the interlayer accommodation of solvated organic cations with controlled sizes during the electrochemical activation of expanded graphite. Our electrochemically activated expanded graphite can be used as an efficient cathode in MOHB with enhanced kinetics, specific capacitance, and cycle life.

In this study, the surface protection film based on organic-inorganic composite is manufactured for suppressing lithium dendrite growth, and the film is applied on the surface of Li metal negative electrode for lithium metal batteries (LMBs). The film is consist of the polyvinylidene fluoride (PVDF) polymeric binder which has good mechanical strength and high electrochemical stability, and carbon black (Super-P) which has outstanding electrical conductivity as the inorganic compound. First, in order to confirm the suppression of the internal short circuit by the lithium dendrite, the time required for the short circuit is measured while a constant current is continuously applied. As a result, the internal short circuit is delayed in proportion to the carbon black content of the film, and it is significantly delayed than bare Li metal electrode which does not use protection film. The cycle performance of the thick protection film (8 mu m), is worse than that of the thin film (4 mu m). However, as the carbon black content of the film increased, the cycle performance is improved. Thus, the surface protection film based on carbon black/PVDF composite can delay the internal short circuit, and has low overvoltage during the cycle. However, more stable cycle performance needs to be built through further improvements.