Surface Modification on Nickel Rich Cathode Materials for Lithium-Ion Cells: A Mini Review

LiAlSiO4-coated Li1.2Mn0.54Ni0.13Co0.13O2 cathode: Enhancing Li-ion battery performance

The lithium fast ion conductor LiAlSiO4 demonstrates exceptional lithium-ion transmission properties alongside remarkable chemical stability. Utilizing sol-gel techniques, we synthesized LiAlSiO4-coated cathode materials (LNCM@LASO) based on Li1.2Mn0.54Ni0.13Co0.13O2 to enhance their electrochemical performance. Rm space groups were identified in all materials through high-intensity diffraction peaks, indicating the presence of hexagonal layered α-NaFeO2 structures. Benefiting from the coating layer of LiAlSiO4, the conductivity and electrochemical performance of Li1.2Mn0.54Ni0.13Co0.13O2 are significantly improved. Compared with the unmodified LASO-0 sample (42.27%), the LASO-3 sample exhibits a superior initial coulomb efficiency of 66.02%. At various charge/discharge rates (0.1, 0.2, 0.5, 1, and 2 C), the LASO-3 electrode exhibits specific discharge capacities of 210.6, 189.3, 168.1, 151.8, and 125.2 mAh·g-1, correspondingly. Upon reverting the current density from 2 C to 0.1 C, the discharge capacity of the LASO-3 electrode rebounds to 206.4 mAh·g-1. After 100 cycles at 0.1 C, the LASO-3 electrode achieves a peak capacity retention rate of 88.9%. The superior conductive properties and chemical stability of the LNCM@LASO enhance the electron and ion transfer, thereby preventing electrolyte attack and boosting the electrochemical performance. This research marks a crucial step towards developing high-capacity, low-cost lithium-ion batteries with wide-ranging implications across multiple disciplines and industries.

Boosting Anionic Redox Reactions of Li-Rich Cathodes through Lattice Oxygen and Li-Ion Kinetics Modulation in Working All-Solid-State Batteries

The use of lithium-rich manganese-based oxides (LRMOs) as the cathode in all-solid-state batteries (ASSBs) holds great potential for realizing high energy density over 600 Wh kg-1. However, their implementation is significantly hindered by the sluggish kinetics and inferior reversibility of anionic redox reactions of oxygen in ASSBs. In this contribution, boron ions (B3+) doping and 3D Li2B4O7 (LBO) ionic networks construction are synchronously introduced into LRMO materials (LBO-LRMO) by mechanochemical and subsequent thermally driven diffusion method. Owing to the high binding energy of B─O and high-efficiency ionic networks of nanoscale LBO complex in cathode materials, the as-prepared LBO-LRMO displays highly reversible and activated anionic redox reactions in ASSBs. The designed LBO-LRMO interwoven structure enables robust phase and LBO-LRMO|solid electrolyte interface stability during cycling (over 80% capacity retention after 2000 cycles at 1.0 C with a voltage range of 2.2-4.7 V vs Li/Li+). This contribution affords a fundamental understanding of the anionic redox reactions for LRMO in ASSBs and offers an effective strategy to realize highly activated and reversible oxygen redox reactions in LRMO-based ASSBs.

Redox Couple Strategy for Improving the Oxygen Redox Activity and Reversibility of Li- and Mn-Rich Cathode Materials

The specific capacity of Li- and Mn-rich layered oxide (LMROs) cathodes can be enhanced by the oxidation of lattice oxygen at high voltages. Nevertheless, an irreversible oxygen loss emerges with cycling, which triggers interlocking surface/interface issues and results in the fast deterioration of cycling performance. Herein, we prepare a surface modified LMRO electrode by one step doctor-blade casting and introducing a benzoquinone species DBBQ redox couple. The electrochemical test shows that the DBBQ-modified electrode has a high reversible capacity (>320 mAh g-1) and excellent rate performance, while the cyclic stability has been significantly improved as well. The capacity retention reaches as high as 93.3% after 500 cycles at 1 C. Mechanism analysis shows that DBBQ can not only play a redox couple in LMROs which achieves the adsorption and reduction of surface oxygen gas but also significantly enhance anionic redox in the bulk, thus realizing extraordinary capacity.

Doping Effects on Ternary Cathode Materials for Lithium-Ion Batteries: A Review

The ongoing advancements in lithium-ion battery technology are pivotal in propelling the performance of modern electronic devices and electric vehicles. Amongst various components, the cathode material significantly influences the battery performance, such as the specific capacity, capacity retention and the rate performance. Ternary cathode materials, composed of nickel, manganese, and cobalt (NCM), offer a balanced combination of these traits. Recent developments focus on elemental doping, which involves substituting a fraction of NCM constituent ions with alternative cations such as aluminum, titanium, or magnesium. This strategic substitution aims to enhance structural stability, increase capacity retention, and improve resistance to thermal runaway. Doped ternary materials have shown promising results, with improvements in cycle life and operational safety. However, the quest for optimal doping elements and concentrations persists to maximize performance while minimizing cost and environmental impact, ensuring the progression towards high-energy-density, durable, and safe battery technologies.

Advances of LiCoO2 in Cathode of Aqueous Lithium-Ion Batteries

Aqueous lithium-ion batteries offer promising advantages such as low cost, enhanced safety, high rate capability, and the ability to deliver considerable capacity at 1.8 V, making them ideal candidates for large-scale reserve power sources for renewable energy. However, the practical application of aqueous lithium-ion batteries has been hindered by the poor cycle stability of layered cathode materials, including LiCoO2, in neutral aqueous electrolytes. This review examines the working principles, material limitations, and research progress of aqueous lithium-ion batteries. The types and characteristics of materials used in the cathode of aqueous lithium-ion batteries are summarized, with a primary focus on the attenuation mechanisms of LiCoO2 when used as the cathode material in aqueous electrolytes. Furthermore, this review explores the advancements in utilizing LiCoO2 in the cathode of aqueous lithium-ion batteries, as well as the combination with machine learning. By addressing these critical aspects, this review aims to provide a comprehensive understanding of aqueous lithium-ion batteries and shed light on future development and application prospects.

Two birds with one stone: One-pot concurrent Ta-doping and -coating on Ni-rich LiNi0.92Co0.04Mn0.04O2 cathode materials with fiber-type microstructure and Li+-conducting layer formation

A novel scalable Taylor-Couette reactor (TCR) synthesis method was employed to prepare Ta-modified LiNi0.92Co0.04Mn0.04O2 (T-NCM92) with different Ta contents. Through experiments and density functional theory (DFT) calculations, the phase and microstructure of Ta-modified NCM92 were analyzed, showing that Ta provides a bifunctional (doping and coating at one time) effect on LiNi0.92Co0.04Mn0.04O2 cathode material through a one-step synthesis process via a controlling suitable amount of Ta and Li-salt. Ta doping allows the tailoring of the microstructure, orientation, and morphology of the primary NCM92 particles, resulting in a needle-like shape with fine structures that considerably enhance Li+ ion diffusion and electrochemical charge/discharge stability. The Ta-based surface-coating layer effectively prevented microcrack formation and inhibited electrolyte decomposition and surface-side reactions during cycling, thereby significantly improving the electrochemical performance and long-term cycling stability of NCM92 cathodes. Our as-prepared NCM92 modified with 0.2 mol% Ta (i.e., T2-NCM92) exhibits outstanding cyclability, retaining 84.5 % capacity at 4.3 V, 78.3 % at 4.5 V, and 67.6 % at 45 ℃ after 200 cycles at 1C. Even under high-rate conditions (10C), T2-NCM92 demonstrated a remarkable capacity retention of 66.9 % after 100 cycles, with an initial discharge capacity of 157.6 mAh g-1. Thus, the Ta modification of Ni-rich NCM92 materials is a promising option for optimizing NCM cathode materials and enabling their use in real-world electric vehicle (EV) applications.

Bio-synthesized TiO2 nanoparticles and the aqueous binder-based anode derived thereof for lithium-ion cells

Titanium dioxide nanoparticles (TiO2-NPs) are a promising anode material for Lithium-ion batteries (LIBs) due to their good rate capability, low cost, non-toxicity, excellent structural stability, extended cycle life, and low volumetric change (∼4%) during the Li+ insertion/de-insertion process. In the present paper, anatase TiO2-NPs with an average particle size of ~ 12 nm were synthesized via a green synthesis route using Beta vulgaris (Beetroot) extract, and the synthesized TiO2-NPs were evaluated as anode material in LIBs. Furthermore, we employed an aqueous binder (1:1 mixture of carboxy methyl cellulose and styrene butadiene) for electrode processing, making the process cost-effective and environmentally friendly. The results revealed that the Li/TiO2 half-cells delivered an initial discharge capacity of 209.7 mAh g-1 and exhibited superior rate capability (149 mAh g-1 at 20 C) and cycling performances. Even at the 5C rate, the material retained a capacity of 82.2% at the end of 100 cycles. The synthesis route of TiO2-NPs and the aqueous binder-based electrode processing described in the present work are facile, green, and low-cost and are thus practically beneficial for producing low-cost and high-performance anodes for advanced LIBs.

Why the Synthesis Affects Performance of Layered Transition Metal Oxide Cathode Materials for Li-Ion Batteries

The limited cyclability of high-specific-energy layered transition metal oxide (LiTMO2) cathode materials poses a significant challenge to the industrialization of batteries incorporating these materials. This limitation can be attributed to various factors, with the intrinsic behavior of the crystal structure during the cycle process being a key contributor. These factors include phase transition induced cracks, reduced Li active sites due to Li/Ni mixing, and slower Li+ migration. In addition, the presence of synthesis-induced heterogeneous phases and lattice defects cannot be disregarded as they also contribute to the degradation in performance. Therefore, gaining a profound understanding of the intricate relationship among material synthesis, structure, and performance is imperative for the development of LiTMO2. This paper highlights the pivotal role of structural play in LiTMO2 materials and provides a comprehensive overview of how various control factors influence the specific pathways of structural evolution during the synthesis process. In addition, it summarizes the scientific challenges associated with diverse modification approaches currently employed to address the cyclic failure of materials. The overarching goal is to provide readers with profound insights into the study of LiTMO2.

Lithium Iron Phosphate and Layered Transition Metal Oxide Cathode for Power Batteries: Attenuation Mechanisms and Modification Strategies

In the past decade, in the context of the carbon peaking and carbon neutrality era, the rapid development of new energy vehicles has led to higher requirements for the performance of strike forces such as battery cycle life, energy density, and cost. Lithium-ion batteries have gradually become mainstream in electric vehicle power batteries due to their excellent energy density, rate performance, and cycle life. At present, the most widely used cathode materials for power batteries are lithium iron phosphate (LFP) and LixNiyMnzCo1-y-zO2 cathodes (NCM). However, these materials exhibit bottlenecks that limit the improvement and promotion of power battery performance. In this review, the performance characteristics, cycle life attenuation mechanism (including structural damage, gas generation, and active lithium loss, etc.), and improvement methods (including surface coating and element-doping modification) of LFP and NCM batteries are reviewed. Finally, the development prospects of this field are proposed.