Search Results (86)

The growing demand for high-energy, safe, and sustainable lithium-ion batteries has increased interest in nickel-rich cathode materials and solid-state electrolytes. This study presents a scalable wet-processing method for fabricating composite cathodes for all-solid-state batteries. The cathodes studied herein are high-nickel LiNi_0.90Mn_0.05Co_0.05O₂, NMC955, the sulfide-based electrolyte Li₆PS₅Cl, and alternative binders—polyvinyl alcohol (PVA) and polyisobutylene (PIB)—dispersed in toluene, a non-polar solvent compatible with the electrolyte. After fabrication, the cathodes were characterized using SEM/EDX, sheet resistance, and Hall effect measurements. Electrochemical tests were additionally performed in all-solid-state battery half-cells comprising the synthesized cathodes, lithium metal anodes, and Li₆PS₅Cl as the separator and electrolyte. The results show that both PIB and PVA formulations yielded conductive cathodes with stable microstructures and uniform particle distribution. Electrochemical characterization exposed that the PVA-based cathode outperformed the PIB-based counterpart, achieving the theoretical capacity of 192 mAh·g⁻¹ even at 1C, whereas the PIB cathode reached a maximum capacity of 145 mAh.g⁻¹ at C/40. Post-mortem analysis confirmed the structural integrity of the cathodes. These findings demonstrate the viability of NMC955 as a high-capacity cathode material compatible with solid-state systems. Full article

Lithium-rich layered oxide (LLO) has received extensive attention from researchers due to its high initial discharge capacity (≥250 mAh g⁻¹). However, defects such as its high initial irreversible capacity, voltage decay, and poor rate performance have severely limited its commercialization. These issues arise because the Li₂MnO₃ component in LLO is activated during the initial cycle, leading to the participation of lattice oxygen anions (O²⁻) in redox reactions. This results in irreversible oxygen loss (O₂) and subsequent structural phase transitions. To address these challenges, this study focuses on Li₁.₂Ni₀.₁₃Co₀.₁₃Mn₀.₅₄O₂ as the host material, utilizing abundant exposed (010) plane secondary particles and employing a vanadium (V) doping strategy to enhance electrochemical performance. The V forms strong V-O bonds with the lattice oxygen, effectively suppressing irreversible oxygen loss and improving structural stability. The results demonstrate that the LLO achieves the best electrochemical performance as the doping amount is 1 mol%, and the capacity retention improves from 74.5% (undoped) to 86% (V-doped) after 140 cycles at 0.5 C. Full article

Li-rich Mn-based cathode materials are considered potential cathode materials for next-generation lithium-ion batteries due to their outstanding theoretical capacity and energy density. Nonetheless, challenges like oxygen loss, transition metal migration, and structural changes during cycling have limited their potential for commercialization. The work in this study employed a straightforward heat treatment to generate oxygen vacancies. This process led to the development of a spinel phase on the surface, which improved Li⁺ diffusion and boosted the electrochemical performance of Li-rich Mn-based oxides. The results demonstrate that the treated Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ exhibits an initial specific capacity of 247 mAh·g⁻¹ at 0.2C, as well as a reversible capacity of 224 mAh·g⁻¹ after 100 cycles, with a capacity retention of 90.7%. The voltage decay is 1.221 mV per cycle under 1C long-term cycling conditions, indicating excellent cycling stability and minimal voltage drop. Therefore, this strategy of engineering through nanoscale oxygen vacancies provides a new idea for the development of high-stability layered oxide anodes and provides a reference for the development and application of new energy materials. Full article

With the growing demand for metals driven by technological advancements and population growth, recycling lithium-ion batteries has become vital for protecting the environment and recovering valuable materials. Developing sustainable recycling technologies is now more essential than ever. This paper focuses on using electrodialysis to process a leach solution of LiNi_0.33Mn_0.33Co_0.33O₂ (NMC 111) cathode materials leached with citric acid. This study demonstrates that the complexing properties of citrate anions contribute to the efficient separation of Li from Ni, Co, and Mn by electrodialysis. This is achieved by promoting the formation of anionic species for Ni, Co, and Mn while maintaining Li in its cationic form. The leach solution was produced under the following optimal experimental conditions to reach a final pH of 5 and high leaching efficiency: a citric acid concentration of 1 mol L⁻¹, a leaching temperature of 45 °C, a leaching time of 5 h, a liquid/solid ratio of 100 g/L, and 8 vol.% H₂O₂. These conditions resulted in leaching efficiencies of 89.3% for Ni, 95.1% for Co, 77.1% for Mn, and 92.9% for Li. This solution led to the formation of a lithium-rich supernatant and a precipitate. The supernatant was then used as the feed solution for electrodialysis. Pure lithium was successfully separated with a faradic efficiency of 71.4% with a commercial cation-exchange membrane. This strategy enables selective lithium recovery while minimizing membrane fouling during the process. Full article

La-doped Li_1.2Ni_0.13Mn_0.54Co_0.13O₂ cathode materials were successfully synthesized by the sol-gel method. The structure, morphology, element valence states, cyclic voltammetry, and cyclic properties were characterized to investigate the properties of the synthesized materials. The as-prepared La-doped Li_1.2Ni_0.13Mn_0.54Co_0.13O₂ materials exhibit well the crystalline hexagonal layered structures with lamellar-like particles featuring a rough surface. The optimal sample, designated as LLRMO-2 with 1/100 La³⁺ doping, delivers an impressive discharge capacity of 271.2 mAh g⁻¹ with a capacity retention of 87.8% after 100 cycles at the current density of 100 mA g⁻¹ compared with that of 203.5 mAh g⁻¹ with only 110.6 mAh g⁻¹ after 100 cycles for the pristine sample. Furthermore, the LLRMO-2 cathode exhibits a superior rate capability compared to the pristine sample and shows excellent cyclic performances with the capacity retention of 48.1% after 400 cycles. The voltage decay per cycle is only 1.60 mV, which is less than 3.70 mV of the pristine one. The enhanced capacity, rate capability, and cyclic performance observed in the La-doped Li-rich layered cathode can be attributed to the improved structural stability as well as the higher diffusion coefficient of lithium ions. These results suggest that the strategy of introducing La³⁺ into the transition metal slabs is an efficient approach for boosting electrochemical performances of Li-rich Mn-based cathode materials via enhancing structural stability. Full article

Nickel-rich cathode materials have emerged as ideal candidates for electric vehicles due to their high energy density; however, polycrystalline materials are prone to microcrack formation and unavoidable side reactions with electrolytes during cycling, leading to structural instability and capacity degradation. Herein, an Sr-doped single-crystalline nickel-rich LiNi_0.88Co_0.05Mn_0.07O₂/Sr cathode material is synthesized, with Sr doping levels controlled at x = 0.3%, 0.5%, 1 mol%. The nickel-rich LiNi_0.88Co_0.05Mn_0.07O₂/Sr cathode features particle sizes of approximately 2 μm, at a relatively low temperature. It inhibits the microcrack formation, prevents electrolyte penetration into the particle interior, and reduce side reactions, thereby enhancing structural stability. This enables the cathode to deliver a high initial discharge capacity of 205.3 mAh g⁻¹at 0.1 C and 170.8 mAh g⁻¹ at 10 C, within the voltage range of 2.7 V–4.3 V, and an outstanding capacity retention of 96.61% at 1 C after 100 cycles. These improvements can be attributed to the Sr-doping, which reduces the single-crystal growth temperature, effectively mitigating Li⁺/Ni²⁺ cation mixing. Moreover, the incorporation of Sr expands the interlayer spacing, thereby facilitating Li⁺ diffusion. The doping strategy employed in this work provides a new insight for low-temperature single-crystal materials synthesis, significantly improving the electrochemical performance of nickel-rich cathode materials. Full article

With the rising popularity of electric vehicles and the widespread deployment of energy storage power stations. The demand for high-energy-density lithium-ion batteries is increasing day by day. Lithium-rich layered materials are among the most promising candidates for the cathode of next-generation lithium-ion batteries due to their high energy density, cost-effectiveness, and advantages in safety and environmental protection. However, the occurrence of side reactions between lithium-rich layered materials and electrolytes has led to poor performance in later stages, posing challenges to their commercial viability. In this study, we enhance the electrochemical performance of lithium-rich layered cathode materials by applying varying amounts of solid electrolyte Li₂ZrO₃ as a coating on their surfaces. By precipitating ZrO₂ onto the surface of the precursor, we successfully sinter both the lithium-rich layered material and the coated material simultaneously, thereby reducing processing costs. The experimental results show that the coated material has more excellent electrochemical performance, specifically, when the coating amount is 1%, compared with the uncoated sample, the first Coulombic efficiency is improved from 56.9% to 63%, and after 500 charge/discharge cycles, the coated sample still has a capacity retention rate of more than 60%; Additionally, the Li₂ZrO₃ coating significantly improves the rate performance of the material, at a rate of 5 C, the specific discharge capacity improved from 102.2 mAh·g⁻¹ for the uncoated material to 137.3 mAh·g⁻¹. The reaction mechanism was investigated by cyclic voltammetry and AC impedance test, and the results showed that the appropriate amount of Li₂ZrO₃ coating can effectively reduce the side reaction between the material and the electrolyte, improve the transport performance of lithium ions in the material, and then enhance the overall electrochemical performance of the material. Full article

Integrated Li- and Mn-rich layered cathodes yLi₂MnO₃∙(1-y)LiMO₂ (M = Mn, Co, and Ni) have shown their ability to deliver specific capacities close to 300 mAh g⁻¹, but their significant drawbacks are capacity fading and voltage decay during cycling. In this study, new stoichiometric high-voltage Li-rich oxides with y = 0.0, 0.3, and 0.5 are synthesized in identical conditions using a sol–gel method. These compositions were analyzed to determine their optimal configuration and to understand their extraordinary behavior. Their nanostructural properties were investigated using XRD and Raman spectroscopy, while the morphology and grain-size distribution of the samples were characterized by BET, SEM and HRTEM analyses. The electrochemical performances of the integrated Li- and Mn-rich compounds were evaluated through galvanostatic cycling and electrochemical impedance spectroscopy. The best cathode material 0.5Li₂MnO₃∙0.5LiNi_1/3Co_1/3Mn_1/3O₂ had a capacity retention of 83.6% after 100 cycles in the potential range 2.0–4.8 V vs. Li⁺/Li. Full article

Due to the advantages of high capacity, low working voltage, and low cost, lithium-rich manganese-based material (LMR) is the most promising cathode material for lithium-ion batteries; however, the poor cycling life, poor rate performance, and low initial Coulombic efficiency severely restrict its practical utility. In this work, the precursor Mn_2/3Ni_1/6Co_1/6CO₃ was obtained by the continuous co-precipitation method, and on this basis, different doping levels of aluminum–magnesium were applied to modify the electrode materials by high-temperature sintering. The first discharge capacity can reach 295.3 mAh·g⁻¹ for the LMR material of Li_1.40(Mn_0.666Ni_0.162Co_0.162Mg_0.005Al_0.005)O₂. The Coulombic efficiency is 83.8%, and the capacity retention rate remains at 84.4% after 300 cycles at a current density of 1 C for the Mg-Al co-doped LMR material, superior to the unmodified sample. The improved electrochemical performance is attributed to the increased oxygen vacancy and enlarged lithium layer spacing after trace magnesium–aluminum co-doping, enhancing the lithium-ion diffusion and effectively mitigating voltage degradation during cycling. Thus, magnesium–aluminum doping modification emerges as a promising method to improve the electrochemical performance of lithium-rich manganese-based cathode materials. Full article

High Ni-content LiNi_xMn_yCo_zO₂ (NMC) cathodes (with x ≥ 0.8, x + y + z = 1) have gained attention recently for their high energy density in electric vehicle (EV) Li-ion batteries. However, Ni-rich cathodes pose challenges in capacity retention due to inherent structural and surface redox instabilities. One promising strategy is to make the Ni-rich NMC material in the form of single-crystal micron-sized particles, as they resist intergranular and surface degradation during cycling. Among various methods to synthesize single-crystal NMC (SC-NMC) particles, molten-salt-assisted calcination offers distinct processing advantages but at present, is not yet optimized or mechanistically clarified to yield the desired control over crystal growth and morphology. In this project, molten-salt-mediated transformation of Ni_0.85Mn_0.05Co_0.15(OH)₂ precursor (P-NMC) particles to LiNi_0.85Mn_0.05Co_0.15O₂ particles is investigated in terms of the crystal growth mechanism and its electrochemical response. Unlike previous studies that involved large volumes of molten salt, using a smaller volume of molten KCl is found to result in larger primary particles with improved cycling performance achieved via partial reactive dissolution and heterogeneous nucleation growth, suggesting that the ratio of molten salt volume to NMC mass is an important parameter in the synthesis of single-crystal Ni-rich NMC materials. Full article

High-voltage initial anode-free lithium metal batteries (AFLMBs) promise the maximized energy densities of rechargeable lithium batteries. However, the reversibility of the high-voltage cathode and lithium metal anode is unsatisfactory in sustaining their long lifespan. In this research, a concentrated electrolyte comprising dual salts of LiTFSI and LiDFOB dissolved in mixing solvents of dimethyl carbonate (DMC) and fluoroethylene carbonate (FEC) with a LiNO₃ additive was formulated to address this challenge. FEC and LiNO₃ regulate the anion-rich solvation structure and help form a LiF, Li₃N-rich solid electrolyte interphase (SEI) with a high lithium plating/stripping Coulombic efficiency of 98.3%. LiDFOB preferentially decomposes to effectively suppress the side reaction at the high-voltage operation of the Li-rich Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ cathode. Moreover, the large irreversible capacity during the initial charge/discharge cycle of the cathode provides supplementary lithium sources for cycle life extension. Owing to these merits, the as-fabricated AFLMBs can operate stably for 80 cycles even at an ultrahigh voltage of 4.6 V. This study sheds new insights on the formulation of advanced electrolytes for highly reversible high-voltage cathodes and lithium metal anodes and could facilitate the practical application of AFLMBs. Full article

Ni-rich Li(Ni_xCo_yMn_z)O₂ (x ≥ 0.8)-layered oxide materials are highly promising as cathode materials for high-energy-density lithium-ion batteries in electric and hybrid vehicles. However, their tendency to undergo side reactions with electrolytes and their structural instability during cyclic lithiation/delithiation impairs their electrochemical cycling performance, posing challenges for large-scale applications. This paper explores the application of an Al₂O₃ coating using an atomic layer deposition (ALD) system on Ni-enriched Li(Ni_0.8Co_0.1Mn_0.1)O₂ (NCM811) cathode material. Characterization techniques, including X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, were used to assess the impact of alumina coating on the morphology and crystal structure of NCM811. The results confirmed that an ultrathin Al₂O₃ coating was achieved without altering the microstructure and lattice structure of NCM811. The alumina-coated NCM811 exhibited improved cycling stability and capacity retention in the voltage range of 2.8–4.5 V at a 1 C rate. Specifically, the capacity retention of the modified NCM811 was 5%, 9.11%, and 11.28% higher than the pristine material at operating voltages of 4.3, 4.4, and 4.5 V, respectively. This enhanced performance is attributed to reduced electrode–electrolyte interaction, leading to fewer side reactions and improved structural stability. Thus, NCM811@Al₂O₃ with this coating process emerges as a highly attractive candidate for high-capacity lithium-ion battery cathode materials. Full article

To realize high-energy-density Li metal batteries at low temperatures, a new electrolyte is needed to solve the high-voltage compatibility and fast lithium-ion de-solvation process. A gel polymer electrolyte with a small-molecular-weight polymer is widely investigated by combining the merits of a solid polymer electrolyte (SPE) and liquid electrolyte (LE). Herein, we present a new gel polymer electrolyte (P-DOL) by the lithium difluoro(oxalate)borate (LiDFOB)-initiated polymerization process using 1,3-dioxolane (DOL) as a monomer solvent. The P-DOL presents excellent ionic conductivity (1.12 × 10⁻⁴ S cm⁻¹) at −20 °C, with an oxidation potential of 4.8 V. The Li‖LiCoO₂ cell stably cycled at 4.3 V under room temperature, with a discharge capacity of 130 mAh g⁻¹ at 0.5 C and a capacity retention rate of 86.4% after 50 cycles. Moreover, a high-Ni-content LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cell can steadily run for 120 cycles at −20 °C, with a capacity retention of 88.4%. The underlying mechanism of high-voltage compatibility originates from the dense and robust B- and F-rich cathode interface layer (CEI) formed at the cathode interface. Our report will shed light on the real application of Li metal batteries under all-climate conditions in the future. Full article

The ubiquitous deployment of Li-ion batteries (LIBs) in more demanding applications has reinforced the need to understand the root causes of thermal runaway. Herein, we perform a forensic simulation of a real-case failure scenario, using localised heating of Li(Ni_0.5Mn_0.3Co_0.2)O₂ versus graphite 18650 cylindrical cells. This study determined the localised temperatures that would lead to venting and thermal runaway of these cells, as well as correlating the gases produced as a function of the degradation pathway. Catastrophic failure, involving melting (with internal cell temperatures exceeding 1085 °C), deformation and ejection of the cell componentry, was induced by locally applying 200 °C and 250 °C to a fully charged cell. Conversely, catastrophic failure was not observed when the same temperatures were applied to the cells at a lower state of charge (SOC). This work highlights the importance of SOC, chemistry and heat in driving the thermal failure mode of Ni-rich LIB cells, allowing for a better understanding of battery safety and the associated design improvements. Full article

Cobalt-free manganese-based lithium-rich layered oxides (LLOs) have garnered research attention as prospective lithium-ion cathode materials owing to their large specific capacity and low price. However, their large-scale application is hindered by their low Coulombic efficiency, poor cycling performance, voltage attenuation, and structural phase transition. To address these issues, the LLO structure is modified via Ti doping at the manganese site herein. Ti-doped Li_1.2Mn_0.6−xTi_xNi_0.2O₂ (x = 0, 0.03, 0.05, 0.10, and 0.15) is prepared using the high-temperature solid-state method. The Ti-doped Li_1.2Mn_0.6Ni_0.2O₂ is calculated via first principles. The results show that Ti⁴⁺ doping improves the cycle stability and rate performance of Li_1.2Mn_0.6Ni_0.2O₂. Electrochemical test results show that the sample exhibits enhanced electrochemical performance when the Ti doping amount is 0.05. The discharge specific capacity at 0.1C is 210.4 mAh·g⁻¹, which reaches 191.1 mAh·g⁻¹ after 100 cycles, with a capacity retention rate of 90.7%. This study proves the feasibility of using cheap cobalt-free LLOs as cathode materials for LIBs and provides a novel system for exploiting low-cost and high-performance cathode materials. Full article