Cathode Materials For Lithium-ion Batteries Research Articles

Optimal design of LiMn2O4 for high-rate applications by means of citric acid aided route and microwave heating

Due to shortening the duration of the process and possibility to obtain crystals of smaller and uniform size, microwave heating is considered an effective and promising tool for the synthesis of LiMn2O4, a valuable cathode material for lithium-ion batteries. However, electrochemical characteristics of LiMn2O4 obtained with its help are almost completely absent and do not allow for drawing a sound conclusion regarding advantages and drawbacks of microwave processing. Here we present a description of the microwave-assisted citric acid aided synthesis, characterization and electrochemical performance of LiMn2O4. The disclosure of detailed working protocols enabling one to manufacture samples tolerant to extremely high currents is the main novelty of this paper. Specifically, our material sustains current loads up to 40 C (5920 mA g-1) and completely recovers after cycling at harsh conditions.

Multiple-functional LiTi2(PO4)3 modification improving long-term performances of Li-rich Mn-based cathode material for advanced lithium-ion batteries

Li-rich layered oxides with high energy densities have become one kind of promising cathode for advanced lithium-ion batteries, however some issues are severely hindering their practical applications. To address these challenges, fast ion conductive LiTi2(PO4)3 (LTPO) is employed to modify the typical Li-rich cathode Li1·2Mn0·56Ni0·17Co0·07O2 (LMNCO) via a sol-gel process combined with a two-step annealing treatment in this work. Serving as a physical separator, LTPO coating effectively depresses the side reactions at cathode-electrolyte interface and the transition-metal dissolution from LMNCO active material under harsh electrochemical environment. Meanwhile, LTPO layer with high ion conductivity could facilitate the interfacial Li+ diffusion during charge/discharge process. In addition, partial Ti4+ ions doped into LMNCO effectively elevate the oxygen electronegativity and restrain the excessive oxidization of lattice oxygen, thus stabilizing the crystal structure and alleviating the stress-strain propagation upon cycling. Electrochemical characterization results demonstrate that the LTPO-modified LMNCO cathode exhibits a superior capacity retention of 86.5 % after 400 cycles at room temperature and that of 73.7 % even under an elevated temperature of 45 °C after 250 cycles under 1C. This study provides a facile strategy for the surface modification of Li-rich layered-structure oxides, which also sheds light in enhancing electrochemical performances for various cathode materials.

Facile synthesis of a carbon supported lithium iron phosphate nanocomposite cathode material from metal-organic framework for lithium-ion batteries

Lithium iron phosphate (LiFePO4, LFP) has become one of the most widely used cathode materials for lithium-ion batteries. The inferior lithium-ion diffusion rate of LFP crystals always incurs poor rate capability and unsatisfactory low-temperature performances. To meet with the requirements from the ever-growing market, it is of great significance to synthesize carbon supported LFP nanocomposite (LFP/C) cathode materials using cost effective and environmentally friendly methods. In this work, an LFP/C cathode material is straightforwardly prepared from a metal–organic framework (MOF) precursor ferric gallate (Fe-GA) using its self-template effect. The Fe-GA precursor is firstly fabricated from the redox coprecipitation reaction between Fe foils and gallic acid (GA) molecules in mild aqueous phase. Then the Fe-GA is directly converted to the LFP/C sample after a following solid-state reaction. In half-cells, the LFP/C composite exhibits a reversible capacity of 109.7 mAh·g−1 after 500 cycles under the current rate of 100 mA·g−1 at 25 °C as well as good rate capabilities. In the LFP/C//graphite full-cells, the LFP/C composite can deliver a reversible capacity of 71.4 mAh·g−1 after 50 cycles in the same condition as the half-cells. The electrochemical performances of the LFP/C cathode in half-cells at lower temperature of −10 °C are also examined. Particularly, the evolution of samples has been explored and the lithium-ion storage mechanism of the LFP/C cathode has been unveiled. The sample synthesis protocol is straightforward, eco-friendly and atomic efficient, which can be considered to have good potential for scaling-up.

New Insight into Bulk Structural Degradation of High-Voltage LiCoO2 at 4.55 V.

The aggravated mechanical and structural degradation of layered oxide cathode materials upon high-voltage charging invariably causes fast capacity fading, but the underlying degradation mechanisms remain elusive. Here we report a new type of mechanical degradation through the formation of a kink band in a Mg and Ti co-doped LiCoO2 cathode charged to 4.55 V (vs Li/Li+). The local stress accommodated by the kink band can impede crack propagation, improving the structural integrity in a highly delithiated state. Additionally, machine-learning-aided atomic-resolution imaging reveals that the formation of kink bands is often accompanied by the transformation from the O3 to O1 phase, which is energetically favorable as demonstrated by first-principles calculations. Our results provide new insights into the mechanical degradation mechanism of high-voltage LiCoO2 and the coupling between electrochemically triggered mechanical failures and structural transition, which may provide valuable guidance for enhancing the electrochemical performance of high-voltage layered oxide cathode materials for lithium-ion batteries.

Boosting the Electrochemical Performance of Primary and Secondary Lithium Batteries with Mn-Doped All-Fluoride Cathodes.

Transition metal fluorides are potentially high specific energy cathode materials of next-generation lithium batteries, and strategies to address their low conductivity typically involve a large amount of carbon coating, which reduces the specific energy of the electrode. In this study, MnyFe1-yF3@CFx was generated by the all-fluoride strategy, converting most of the carbon in MnyFe1-yF3@C into electrochemical active CFx through a controllable NF3 gas phase fluorination method, while still retaining a tightly bound graphite layer to provide initial conductivity, which greatly improved the energy density of the composite. This synergistic effect of nonfluorinated residual carbon (∼11%) and Mn doping ensures the electrochemical kinetics of the composite. The loading mass of the active substance had been increased to 86%. The theoretical and actual discharge capacity of MnyFe1-yF3@CFx composite was up to 765 mAh g-1 (pure FeF3 is 712 mAh g-1) and 728 mAh g-1, respectively. The discharge capacity at the high-voltage (3.0 V) platform was more than three times higher than that of the non-Mn-doped composite (FeF3@CFx).

Promoted production of aromatic hydrocarbons in biomass catalytic pyrolysis over the coupled catalysts of carbon-reduced waste lithium battery cathode materials and HZSM-5

Inexpensive catalyst sources are of great importance in the conversion of biomass to economically valuable monocyclic aromatic hydrocarbons, and transition metals (Co, Ni, Fe and Mn) rich in catalytic effects in massive waste lithium battery cathode materials are not effectively reutilized currently. For this reason, the feasibility of employing the valuable metal oxides in the carbon-reduced waste lithium battery cathode materials (waste LiFePO4 batteries, LFP, and waste LiNixCoyMn1–x–yO2 batteries, NCM) with HZSM-5 as coupled catalysts in the rape straw catalytic pyrolysis to produce aromatic hydrocarbons was explored. The carbon-reduced waste lithium battery cathode materials performed well at 5 wt% carbon loading, and the content of active components Fe2O3 (SLFPC-5) and NiO (SNCMC-5) used for the reduction of large molecular oxygenates in biomass pyrolysis gas was increased by water leaching treatment. SLFPC-5 demonstrated superior bond-cutting performance, while SNCMC-5 exhibited strong deoxygenation performance. The selectivity of monocyclic aromatic hydrocarbons (MAHs) catalyzed by SLFPC-5/HZSM-5 and SNCMC-5/HZSM-5 was as high as 63.69 % and 79.19 %, with BTX yields of 14.58 wt% and 16.68 wt% respectively. This coupled catalytic system offers a low-cost source of catalysts for biomass catalytic pyrolysis and broadens the possibility of high-value recycling of wasted lithium batteries.

Facile synthesis of LiFePO4/Cu composite as enhanced cathode material for lithium-ion battery by a solid-state grinding method

Lithium iron phosphate (LiFePO4, LFP) is a frequently utilized cathode material for lithium-ion batteries. However, its practical applications are constrained by its relatively low ionic and electronic conductivities. To address this issue, it is possible to utilize highly conductive metallic coatings to enhance the material's electronic conductivity. Herein, LiFePO4 with Cu composites (LFP/Cu) as cathode was synthesized by a simple solid-state process via one-step grinding in the presence of CuNO3 and ascorbic acid. The discharge capacity of the LFP/Cu cathode with 0.75 wt% Cu was found to be 160.9 mA h g−1 at 0.1 C, representing a close approximation of its theoretical capacity and a notable enhancement compared to pure LFP (145.9 mA h g−1). Furthermore, it demonstrates excellent stability with a capacity retention of 136.5 mA h g−1 after 100 cycles at 2 C, as well as good rate performance. The electrochemical impedance spectra demonstrate that the incorporation of copper results in a further reduction in the resistance of LFP/Cu compared to pure LFP. The incorporation of copper particles into lithium iron phosphate has been shown to enhance its electronic conductivity, thereby further enhancing its electrochemical performance. In this study, we present a facile and cost-effective room-temperature synthesis method for the preparation of LiFePO4/Cu composites with improved electrochemical properties. This work provides a promising avenue for the design of cathode materials in lithium-ion batteries.

Boosting interface compatibility of high-voltage LiNi0.5Mn1.5O4 cathode materials with an ionic-conductive Li0.33La0.56TiO3 coating

High voltage LiNi0.5Mn1.5O4 (LNMO) is a crucial cathode material for lithium-ion batteries (LIBs) aiming at high energy densities. However, its performance is hindered by the dissolution of transition metal ions and the instability of the cathode electrolyte interface (CEI) film at elevated voltages. To address these issues, we report a solvothermal method to prepare LNMO coated with Li+-conductor Li0.33La0.56TiO3 (LNMO@LLTO). Our study reveals that the LLTO coating not only enhances ion diffusion at the interface, minimizing the Li+ concentration gradient, and acts as a barrier against Mn-ion dissolution. This coating minimizes side reactions, mitigates structural degradation, and promotes the formation of a stable and balanced CEI film that incorporates LLTO, thus ensuring the long-term cycle stability. When compared to bulk LNMO, the LNMO@LLTO cathode demonstrates superior performance, maintaining reversible capacities of 111.4 and 102.2 mAh·g−1 after 500 cycles at 2 and 5C at 25 °C, respectively. Even at 60 °C, the LNMO@LLTO maintains a high capacity of 94.3 mAh·g−1 with minimal electrochemical polarization after 200 cycles at 2C. This simple preparation technique, together with its performance promotion, offers new insights into the development of high voltage cathode materials for high energy density LIBs.

Construction of multiwall carbon nanotubes/biomass-derived nitrogen-doped carbon@regenerated LiFePO4 cathode materials for lithium-ion batteries

Construction of multiwall carbon nanotubes/biomass-derived nitrogen-doped carbon@regenerated LiFePO4 cathode materials for lithium-ion batteries

Recent advances of cobalt-free and nickel-rich cathode materials for lithium-ion batteries

Recent advances of cobalt-free and nickel-rich cathode materials for lithium-ion batteries

Correlative Survey of Blended LiCoO2 and LiMn2O4 Cathode Materials for Lithium-ion Batteries

We employed the lithium-ion battery model in Multiphysics to simulate the electrochemical characteristics of lithium-ion batteries. These batteries consist of a cathode mixture comprising LiCoO2 and LiMn2O4, as well as quasi-graphite anode. Our simulations successfully replicated the discharge profiles of both unblended and blended cathodes across different current rates, aligning with results obtained from experiments. The energy and power densities of the blended cathode framework were regulated by adjusting the mix ratio in the simulation model. Additionally, the blended electrodes of LiCoO2 and LiMn2O4 demonstrated an above-average electrochemical performance, combining the characteristics of the two active materials.Keywords: Lithium-ion Battery; Blended Cathode Active Materials; Simulation; Experiment

Fast lithium-ion conductor LiTi2(PO4)3 coating modified LiNi0.8Co0.15Al0.05O2 as cathode material for lithium-ion batteries

Fast lithium-ion conductor LiTi2(PO4)3 coating modified LiNi0.8Co0.15Al0.05O2 as cathode material for lithium-ion batteries

The dual modification of La and Zr of Ni-rich cathodes for improved cycling stability at elevated voltage and temperature

Nickel-rich layered oxides are regarded as a promising cathode material for next-generation lithium-ion batteries (LIBs) with advanced power capabilities. However, their poor cycling performance, especially under high voltage and temperature conditions, has seriously limited their large-scale application. In this work, a simple and effective strategy is proposed to enhance the structural and interface stability of Ni-rich materials by La4NiLiO8 coating and Zr doping. The interfacial side reactions and intergranular microcracks of the modified material are inhibited, which is helpful in improving the electrochemical performance. Therefore, the initial capacity of dual modification of La and Zr of Ni-rich cathode is 196.4 mA h g−1 at 4.5 V and exhibits excellent cycling performance with a capacity retention of 82.1 % after 200 cycles. Moreover, at 50 °C, the initial capacity of the modified material is 239.0 mA h g−1, and the capacity retention is 63.1 % after 100 cycles, representing a significant improvement of 94.8 % over the unmodified sample.

Modification of LiMn0·6Fe0·4PO4 lithium-ion battery cathode materials with a fluorine-doped carbon coating

In this study, glucose and NH4F were utilized as sources of carbon and fluorine, respectively, for the synthesis of LiMn0·6Fe0·4PO4 (LMFP) nanoscales. These nanoscales were subsequently modified with varying levels of fluorine-doped carbon through co-precipitation and mechanical ball milling processes. The LMFP, incorporating carbon and varying levels of fluoride ions, exhibit higher specific discharge capacities at 0.2 Cand electrochemical characteristics compared to the original LMFP coated solely with carbon. The inclusion of fluorine-doped carbon in the composite material creates numerous pathways for expeditious electron transfer. Moreover, the partial formation of metal fluoride at the interface between the surface of LMFP and the layer of carbon coating doped with fluorine enhances the reduction in the charge-transfer resistance. The modified ferromanganese phosphate cathode material reveals an outstanding discharge capacity displaying a reversible discharge specific capacity value of 131.73 mA h g−1 at 10C and 154.6 mA h g−1 at 0.2C, due to its unique structure.

A Comprehensive Review on Reductive Recycling of Cathode Materials of Spent Lithium-Ion Batteries.

The prosperity of the lithium-ion battery market is inevitably accompanied by the depletion of corresponding resources and the accumulation of spent batteries in a dialectical manner. Spent lithium-ion batteries are harboring the characteristics of hazardous waste and high-value resources, so efficient recycling is of great significance. The cathode material is considered as an interesting target for repurposing. Despite some important reviews give commendable emphasis to recycling technologies, there is still a dearth of exploration of recycling mechanisms. This deficiency of awareness highlights the need for further research and development in this area. This review aims to systematically review and thoroughly discuss the reduction reaction mechanism of each method regarding different cathode materials. And systematically digest the selection of reducing agent and the effect of reduction reaction on material regeneration are systematically digested, as well as the impact of the reduction reaction on the regeneration of materials. This review emphasizes the importance of balancing efficiency, economic and environmental benefits in reuse technologies. Finally, the review proposes an outlook on the opportunities and challenges facing the reuse of key materials for next-generation spent batteries aimed at promoting the green and sustainable development of lithium-ion batteries, circular economy and ecological balance.

Mn and Ti Co-doping of LiNiO2 to Improve Performance

LiNiO2 (LNO) has high capacity but suffers from structural instability and capacity fade, which limits its practical use in lithium-ion batteries. This study proposes co-doping LNO with Mn and Ti (MnTi25) as a strategy to overcome these issues. MnTi25 was thoroughly characterized, revealing improved structural stability and significantly reduced cation mixing compared to pristine LNO. The half-cell performance of MnTi25 is impressive, exhibiting a capacity similar to the established 4% Mn-substituted ZoomWeMn4 standard, demonstrating efficient Li-ion extraction and insertion. Additionally, full-cell testing against a graphite anode shows that MnTi25 delivers a capacity almost identical to a commercial LNO-based material. This remarkable achievement highlights the effectiveness of co-doping in addressing LNO's limitations while preserving its high-capacity potential. This study demonstrates that MnTi25 can be a promising cathode material for high-performance lithium-ion batteries by tailoring the material's structure through co-doping.

Effects of transition metal ions migration at the cathode|electrolyte interface on the performance of thin-film Lithium-ion batteries with NCM cathodes

The advent of all-solid-state thin-film lithium-ion batteries (LIBs) has revolutionized the powering of microsystems due to their miniaturization ease and seamless integration capabilities. Despite the pressing demand for LIBs with higher energy density and enhanced safety, the performance of these devices has been consistently hindered by the complex interfacial dynamics at the cathode|electrolyte boundary. This study delves into the nuanced characterization of transition metal (TM) ions at the cathode|electrolyte interface, utilizing LiNi0.5Co0.2Mn0.3O2 (NCM523) thin films as the cathode material for LIBs. We meticulously explored the profound impact of NCM523|LiPON interfacial properties on the LIBs' overall performance, uncovering that the migration of TM ions and the emergence of TM–O spinel phases, induced by targeted annealing treatments of the cathodes, play pivotal roles in dictating the battery's capacity density and cycling stability. Heat treatments at 600 and 800 °C led to the formation of inhomogeneous spinel-phase nanolayers on the surfaces of NCM523 thin films, which hindered Li+ transport and affected the LIBs. In stark contrast, the 700 °C treatment yielded a pristine layered structure with clear boundary against LiPON, culminating in a battery with outstanding capacity density and remarkable cycle stability. Our theoretical calculations have unraveled that the temperature-dependent migration of TM ions is intricately linked to the varying strengths of TM–O bonds and the associated Jahn-Teller effects, providing a novel perspective on the design of high-performance LIBs.

Borate modified Co-free LiNi0.5Mn1.5O4 cathode material: A pathway to superior interface and cycling stability in LNMO/graphite full-cells

Cobalt-free LiNi0.5Mn1.5O4 (LNMO) holds great promise as a next-generation cathode material for high-energy and high-power density lithium-ion batteries (LIBs), making it a key contender for large-scale energy storage systems (ESS) and transportation applications. Despite its potential, the commercial utilization of LNMO has been impeded by its rapid capacity deterioration attributed to an unstable LNMO/electrolyte interface caused by the intrinsically high operating voltage of LNMO. Here, we present a pragmatic and scalable strategy to improve the LNMO/electrolyte interface through borate-based surface coating of the LNMO. Optimizing the coating process yielded high-rate capability and stable LNMO/electrolyte interface analyzed by extended float tests. Borate-LNMO materials show superior cycling stability at 25 °C and 45 °C, attributed to a robust cathode electrolyte interphase (CEI) formation. The bare LNMO and 0.25-B2O3-LNMO demostrated a cycling stability of around 41.20 % and 62.50 % respectively after 1000 cycles in LNMO/graphite full-cells. Post-mortem X-ray photoelectron spectroscopy (XPS) analysis revealed fewer side reaction products on borate-LNMO cathodes compared to bare LNMO. Additionally, scanning electron microscopy (SEM) revealed a thicker and denser solid-electrolyte interphase (SEI) on cycled graphite anodes from bare LNMO cells, while a thin and robust SEI was observed on graphite from borate-LNMO cells. Finally, we have conclusively demonstrated that the primary aging mechanism in LNMO/graphite full cells stems from the instability at the LNMO/electrolyte or/and graphite/electrolyte interface, rather than material-related degradation phenomenon. These compelling outcomes underscore the potential of cathode material surface coating in general and especially of borate coating on LNMO as a promising and cost-effective enabler for the use of LNMO in next-generation LIBs.

“Acid + Oxidant” Treatment Enables Selective Extraction of Lithium from Spent NCM523 Positive Electrode

With the rapid development of new energy vehicles and energy storage industries, the demand for lithium-ion batteries has surged, and the number of spent LIBs has also increased. Therefore, a new method for lithium selective extraction from spent lithium-ion battery cathode materials is proposed, aiming at more efficient recovery of valuable metals. The acid + oxidant leaching system was proposed for spent ternary positive electrode materials, which can achieve the selective and efficient extraction of lithium. In this study, 0.1 mol L−1 H2SO4 and 0.2 mol L−1 (NH4)2S2O8 were used as leaching acid and oxidant. The leaching efficiencies of Li, Ni, Co, and Mn were 98.7, 30, 3.5, and 0.1%, respectively. The lithium solution was obtained by adjusting the pH of the solution. Thermodynamic and kinetic studies of the lithium leaching process revealed that the apparent activation energy of the lithium leaching process is 46 kJ mol−1 and the rate step is the chemical reaction process. The leaching residue can be used as a ternary precursor to prepare regenerated positive electrode materials by solid-phase sintering. Electrochemical tests of the regenerated material proved that the material has good electrochemical properties. The highest discharge capacity exceeds 150 mAh g−1 at 0.2 C, and the capacity retention rate after 100 cycles exceeds 90%. The proposed new method can extract lithium from the ternary material with high selectivity and high efficiency, reducing its loss in the lengthy process. Lithium replenishment of the delithiation material can also restore its activity and realize the comprehensive utilization of elements such as nickel, cobalt, and manganese. The method combines the lithium recovery process and the material preparation process, simplifying the process and saving costs, thus providing new ideas for future method development.

The oxidation reaction mechanism and its kinetics for a carbonaceous precursor prepared from ethylene tar for use as a cathode material for lithium-ion batteries

The oxidation reaction mechanism and its kinetics for a carbonaceous precursor prepared from ethylene tar for use as a cathode material for lithium-ion batteries