Cycle Discharge Capacity Research Articles

Enhancing micro-scale SiOx anode durability: Electro-mechanical strengthening of binder networks via anchoring carbon nanotubes with carboxymethyl cellulose

With the increasing prevalence of lithium-ion batteries (LIBs) applications, the demand for high-capacity next-generation materials has also increased. SiOx is currently considered a promising anode material due to its exceptionally high capacity for LIBs. However, the significant volumetric changes of SiOx during cycling and its initial Coulombic efficiency (ICE) complicate its use, whether alone or in combination with graphite materials. In this study, a three-dimensional conductive binder network with high electronic conductivity and robust elasticity for graphite/SiOx blended anodes was proposed by chemically anchoring carbon nanotubes and carboxymethyl cellulose binders using tannic acid as a chemical cross-linker. In addition, a dehydrogenation-based prelithiation strategy employing lithium hydride was utilized to enhance the ICE of SiOx. The combination of these two strategies increased the CE of SiOx from 74% to 87% and effectively mitigated its volume expansion in the graphite/SiOx blended electrode, resulting in an efficient electron-conductive binder network. This led to a remarkable capacity retention of 94% after 30 cycles, even under challenging conditions, with a high capacity of 550 mA h g−1 and a current density of 4 mA cm−2. Furthermore, to validate the feasibility of utilizing prelithiated SiOx anode materials and the conductive binder network in LIBs, a full cell incorporating these materials and a single-crystalline Ni-rich cathode was used. This cell demonstrated a ∼27.3% increase in discharge capacity of the first cycle (∼185.7 mA h g−1) and exhibited a cycling stability of 300 cycles. Thus, this study reports a simple, feasible, and insightful method for designing high-performance LIB electrodes.

Performance of Lithium–Sulfur Battery with Ionic Liquids for Deep Space Environment under High Radiation Dose

INTRODUCTION Recently, lithium–ion batteries (LIBs) about to be applied to satellites for deep space exploration with a long range because of their long cycle life and high energy density. However, the energy density of LIBs is not high enough to be used as batteries for deep space exploration. Therefore, lithium–sulfur batteries (Li–S batteries), which are expected to have a higher energy density than LIBs, seem attractive for deep space exploration. In addition, batteries for the deep space exploration must be made of materials that are resistant to radiation and vacuum. In our previous study, N–methyl–N–propylpyrrolidinium bis(fluorosulfonyl)imide (MPPyFSI) of the ionic liquid was found to be resistant to the radiation (12 krad), which is expected in Earth orbit, and be applicable as an electrolyte for LIBs1). However, it was reported that the specific capacity of the Li–S batteries with MPPyFSI decreased after irradiation to the dose (55 Mrad) expected in the deep space environment, and that it could not be cycled2). In this study, to develop an electrolyte for stable operation of Li–S batteries under deep space environment, we applied a new electrolyte using an ionic liquid to Li–S batteries and investigated the effect of irradiation dose (e.g., 55 Mrad) on the battery and battery materials in deep space environment. Experiment The active material was mixed with microporous activated carbon loaded with 36 wt. % sulfur, acetylene black, and magnesium alginate in a weight ratio of 90 : 3 : 7. The resulting slurry was applied on an Al foil and used as the sulfur cathode. A microporous polyimide membrane was used as the separator, 1.2 mol kg−1 lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) / MPPyFSI as the electrolyte, and 1.0 mol kg−1 lithium hexafluorophosphate (LiPF6) / MPPyFSI were prepared and used. A two–electrode laminated cell was fabricated with the above configuration, and constant–current charge–discharge tests were conducted. The voltage range was 1 – 3 V and the current density was 0.1 C. After 15 cycles of charge–discharge, irradiation tests were conducted on the fully charged cells. The irradiation tests were carried out at Laboratory for Advanced Nuclear Energy, Tokyo Institute of Technology, and 60Co was used as the γ–ray source. The irradiation dose was 20 Mrad. After the irradiation tests, constant–current charge–discharge tests were performed again under the same conditions as above. Results and Discussion Constant–current charge–discharge tests were carried out to investigate the cycling characteristics of Li–S batteries with 1.0 mol kg−1 LiPF6 / MPPyFSI before and after irradiation (irradiation dose 20 Mrad). In the 30th cycle after irradiation, the discharge capacity was 285.5 mAh g−1 and the capacity retention was 23.6% (= discharge capacity of the 30th cycle / discharge capacity of the 15th cycle × 100 [%]). Although the polarization increased and the capacity decreased after irradiation, the Li–S batteries with 1.0 mol kg−1 LiPF6 / MPPyFSI showed stable cycle characteristics, confirming that the Li–S batteries with 1.0 mol kg−1 LiPF6 / MPPyFSI can maintain its electrochemical performance even after irradiation. This indicates that the LiPF6 / MPPyFSI system is resistant to high intensity radiation (γ–rays). The authors would like to express their sincere appreciation to Mr. Isao Yoda, Senior Technical Specialist, Laboratory for Advanced Nuclear Energy, Tokyo Institute of Technology, for his cooperation in the irradiation experiments in this study. Reference 1) M. Yamagata, Y. Sone, S. Nakasuka, M. Kono, M. Ishikawa et al., Electrochemistry, 83 (2015) 918.2) A. Matsushima et al., the 61st Battery Symposium Japan, 1H02 (2020).

Cathode Performance of ZnMn₂O₄ for Zn Anode Rechargeable Batteries

Zinc anode rechargeable batteries (ZABs) are expecting a promising rechargeable battery for next-generation power systems due to a low cost, environmental compatibility, high safety, and high energy density of Zn anode. Although various cathode materials are currently being investigated, no cathode material with high discharge capacity, cycle stability, and high potential has been reported1 . At present, MnO2 is the most promising materials however, cycle stability is still not enough high. In this study, ZnMn2O4 which is the inactive phase of Zn-MnO2 battery using alkaline electrolyte, was focused as cathode using various acidic electrolyte. Optimization of dopant and also additives to electrolyte was studied.ZnMn2O4 was synthesized with spray pyrolysis method using nitrate solution of Zn and Mn. The cathode was prepared by mixing ZnMn2O4, acetylene black, and PTFE at 7:2:1 weight ratio and pressed onto Ti mesh. The cell consists of Zn anode, glass separator, and the ZnMn2O4 cathode prepared. Charge-discharge measurements were performed in constant current mode with three electrodes cell at current density of 0.2 mA/cm².The prepared ZnMn2O4 powder was a sphere shape and SEM observation suggest that inner of particles are vacant, microcapsule structure. Among the electrolytes examined, 3M Zn(OTf)₂+0.1M Mn(OTf)₂ and 3M ZnSO₄+0.1M MnSO₄ were found to be suitable from cycle stability and discharge capacity. In particular, Zn-ZnMn2O4 cell using 3 M Zn(OTf)₂+0.1M Mn(OTf)2 shows discharge capacity larger than 200mAh/g and more than 50 cycles of charge and discharge.Ex situ XRD showed that the MnO peak was appeared after discharge from 1.9 to 0.8V and it is disappeared to be ZnMn2O4 peaks after charge to 1.9V. Consequently, the charge and discharge of Zn-ZnMn2O4 cell is stored electricity by the redox reaction between Mn2+ and Mn3+. Considering the stable discharge capacity and high potential, Zn-ZnMn2O4 battery is highly interesting as rechargeable large capacity battery. Acknowledgement; This presentation is based on results obtained from a project, JPNP21006, commissioned by the New Energy and Industrial Technology Development Organization (NEDO), Japan.1) N. Zhang, X. Chen, M. Yu, Z. Niu, F. Cheng, J. Chen, Chem Soc Rev, 2020, 49, 4203. Figure 1

MnO2@Fe2O3 Cathode for Aqueous Zinc/Manganese Batteries: Enhanced Discharge Capacity and Stability through Forming FeMnO3

Rechargeable Zn/MnO2 batteries suffer from limited cycle life and low capacity. We utilized MnO2@Fe2O3 as the cathode material, achieving a discharge capacity of 290 mAh g−1 at 1 A g−1. The Zn/MnO2@Fe2O3 battery maintained over 90% coulombic efficiency after 1800 cycles at 1 A g−1. Even at 5 A g−1, it reached 154 mAh g−1. The addition of Fe2O3 changed the reaction mechanism and realized the MnO2@Fe2O3 transformation between MnO2@Fe2O3 and MnOOH, FeMnO3 based on the co-doping and conversion of H+/Fe(III). This study underscores the immense potential of the MnO2@Fe2O3 electrode in energy storage applications and highlights the significance of Fe2O3 in enhancing cathode cycling stability and discharge capacity.

Enhanced Vanadium Redox Flow Battery Performance with New Amphoteric Ion Exchange Membranes.

Vanadium redox flow batteries (VRFBs) depend on the separator membrane for their efficiency and cycle life. Herein, two amphoteric ion exchange membranes are synthesized, based on sulfonic acid group-grafted poly(p-terphenyl piperidinium), for VRFBs. Using ether-free poly(p-terphenyl piperidine) (PTP) as the polymer matrix, and sodium 2-bromoethanesulphonate (ES) and 1,4-butane sultone (BS) as grafting agents, We achieve quaternization of PTP through an environmentally friendly process without alkaline catalysts. PTP-ES and PTP-BS membranes exhibit low area resistance, high H+ permeability, and significantly reduced vanadium ion permeability, leading to exceptional ion selectivity, which is 3.06×106Smincm-3 and 4.34×106Smincm-3, respectively,three orders of magnitude higher than that of Nafion115 (0.27×104Smincm-3). The VRFB with PTP-BS achieves a self-discharge duration of 190h, compared to 86h for Nafion 115. Additionally, under current densities of 40-160mAcm-2, PTP-BS shows coulombic efficiencies of 98.1-99.1% and energy efficiencies of 92.0-82.1%, outperforming Nafion 115. The VRFB with PTP-BS also demonstrates excellent cycle stability and discharge capacity retention over 300 cycles at 100mAcm-2. Therefore, the amphoteric PTP-BS membrane shows remarkable performance, offering significant potential for VRFB applications.

Enhanced reversible reaction of hexagonal SnS2@rGO as anode materials for lithium-ion batteries: Analysis of the morphological change mechanism

Tin-based materials have attracted attention as a promising anode material for lithium-ion batteries due to their high theoretical capacity and alloy metal characteristics. However, the structure tends to easily collapse with repetitive charging and discharging processes, leading to volume expansion. The conversion step in the SnS2 reaction mechanism is also sometimes considered irreversible. To address these challenges, this study synthesized layered hexagonal 2D structure-type SnS2 using the oleylamine as surfactant through a wet chemical process. Subsequently, SnS2@rGO was synthesized after compounding with reduced graphene oxide (rGO), utilizing a smaller amount of nanomaterials compared to rGO, showing optimal efficiency. The morphological changes in SnS2 and SnS2@rGO during the charging and discharging processes was revealed that pulverization occurred more slowly in SnS2@rGO compared to SnS2. We quantified the volume expansion rates of SnS2 and SnS2@rGO electrodes, demonstrating that rGO effectively reduces volume expansion. Additionally, an analysis of lithiation mechanism through a comprehensive analysis method using CV, ex-situ XRD, and ex-situ TEM demonstrated that SnS2@rGO enhanced Li+ storage characteristics compared to SnS2, resulting in more reversible chemical changes. rGO and bare SnS2 show poor capacities 307.23 mAh/g and 87.17 mAh/g after 120 cycles, respectively. However bare SnS2 anchored on the surface of rGO exhibits increased electrical conductivity and improved performance (711 mAh/g after 120 cycles), confirming that rGO plays an important role. SnS2@rGO showed enhanced cycling stability and discharge capacity as shown in the electrochemical testing.

Lithium fluorosulfonate-induced low-resistance interphase boosting low-temperature performance of commercial graphite/LiFePO4 pouch batteries

The performance of Li-ion batteries (LIBs) at sub-ambient temperatures is limited by the resistive interphases due to electrolyte decomposition, particularly on the anode surface. In this study, lithium fluorosulfonate (LFS) was added to commercial electrolytes to enhance the low-temperature electrochemical performance of LiFePO4 (LFP)/graphite (Gr) pouch cells. The addition of LFS significantly reduced the charge transfer resistance of the anode, substantially extending the cycle life and discharge capacity of commercial LFP/Gr pouch cells at −10 and −30 °C. Compared with the capacity retention rate of the baseline electrolyte at −10 °C (80 % after 25cycles), the capacity retention rate of the LFS electrolyte after 100 cycles under 0.5 C/0.5 C was retained at 94 %. Further mechanistic studies showed that the LFS additive induced the formation of a solid electrolyte interphase (SEI) film comprising inorganic-rich LiF, Li2SO4, and additional organic fluorides and sulfides to maintain good stability at the Gr/electrolyte interface during low-temperature operation. LFS suppressed electrolyte decomposition by forming a robust and low-resistance SEI film on the anode. These results demonstrate that LFS is a promising electrolyte additive for low-temperature LFP/Gr pouch cells.

Characteristics of hydride electrodes using Mg-Ti-Ni-Co-Al-based alloys synthesized by mechanical milling

For Ni-MH batteries, crystalline Mg-based alloys such as MgNi, Mg2Ni, REMg12, and La2Mg17 are regarded as hopeful negative electrode materials. Even though these alloys are inexpensive and have promising discharge capacity, they hardly ever electrochemically absorb or desorb hydrogen at room temperature. In this paper, the MgNi-based Mg50-xTixNi45Al3Co2 (x = 0, 1, 2, 3, 4) alloy electrodes were fabricated. The surface of the as-cast alloys was modified by mechanical Ni coating. The nanocrystalline and amorphous Mg50-xTixNi45Al3Co2 (x = 0, 1, 2, 3, 4) + 50 wt%Ni alloys for Ni-MH batteries were prepared using mechanical ball milling. The effects of Ti content and ball milling time on the structure and electrochemical hydrogen storage properties of the alloys were investigated. The electrochemical testing reveals that the as-milled alloys can electrochemically absorb and desorb hydrogen well at room temperature. Without any activation, the milled alloys can achieve maximum discharge capacity in the first cycle. With the extension of ball milling time and the increase of Ti content, the cycle stability and discharge capacity of the alloys are significantly enhanced. The electrochemical impedance spectrum, high rate discharge ability, potentiodynamic polarization curve, and potential-step measurement all indicate that the electrochemical kinetics of the prepared alloys initially increase and subsequently decrease with the increase of Ti content, while significantly improve with the prolongation of milling time.

Realizing Dual Functions through Y2O3 Modification to Enhance the Electrochemical Performance of LiNi0.8Co0.1Mn0.1O2 Material

In recent years, the remarkable energy density of high-nickel ternary materials has captured considerable attention. Nevertheless, the high-nickel ternary cathode material encounters several challenges, including cationic mixing, microcrack formation, poor cycling capability, and limited thermal stability. Coating, as a viable approach, proves to be effective in enhancing the material properties. In this study, the LiNi0.8Co0.1Mn0.1O2 (NCM811) sample underwent a dry grinding process, followed by Y2O3 coating and subsequent sintering at varying temperatures. The microstructure, morphology, and electrochemical properties of the materials were meticulously examined, and the underlying mechanism of coating modification was meticulously explored. The outcomes demonstrate the attainment of dual coating and doping effects through Y2O3 modification. Y2O3 coating mitigates the direct interaction between the NCM811 surface and the electrolyte, thereby inhibiting undesired side reactions at the interface. Moreover, the Y element infiltrates the crystal structure, imparting stability at elevated sintering temperatures. Remarkably, the Y2O3-coated cathode materials exhibit significantly enhanced cycling stability, discharge capacity, and rate performance. These findings can provide novel insights that can be harnessed to improve the energy density cathode material of NCM811.

Identifying key determinants of discharge capacity in ternary cathode materials of lithium-ion batteries

Although lithium-ion batteries (LIBs) currently dominate a wide spectrum of energy storage applications, they face challenges such as fast cycle life decay and poor stability that hinder their further application. To address these limitations, element doping has emerged as a prevalent strategy to enhance the discharge capacity and extend the durability of Li-Ni-Co-Mn (LNCM) ternary compounds. This study utilized a machine learning-driven feature screening method to effectively pinpoint four key features crucially impacting the initial discharge capacity (IC) of Li-Ni-Co-Mn (LNCM) ternary cathode materials. These features were also proved highly predictive for the 50th cycle discharge capacity (EC). Additionally, the application of SHAP value analysis yielded an in-depth understanding of the interplay between these features and discharge performance. This insight offers valuable direction for future advancements in the development of LNCM cathode materials, effectively promoting this field toward greater efficiency and sustainability.

Improved electrochemical performance of Co-free Ni-rich cathode material for lithium-ion battery through multi-element composite modification

Layered Co-free Ni-rich materials are considered as promising cathode for lithium-ion batteries (LIBs) due to their high energy density and low cost advantages. However, the serious chemical-mechanical instability and poor cycle life of Co-free Ni-rich cathode materials could hinder their commercialization. Herein, we successfully prepared Mg/Ti/Sb co-doped and CeO2-coated LiNi0.9Al0.1O2 cathode material (M-LNA90) using a composite modification strategy with four inexpensive metal elements. Compared with the unmodified pristine LiNi0.9Al0.1O2 cathode material (P-LNA90), the cycling stability, rate performance, and discharge capacity of the M-LNA90 cathode were significantly improved, and the high-voltage performance was also excellent. At a high voltage of 2.8–4.5 V and 1 C, the capacity retention of M-LNA90 after 100 cycles reached 90.2 % (from 200 mAh g–1 to 181 mAh g–1), which was much higher than that the 60.1 % of P-LNA90 (from 192 mAh g–1 to 115 mAh g–1). Meanwhile, the structure and surface stability of M-LNA90 cathode showed excellent, which effectively suppressed particle cracking and interfacial side reactions. This work provides a new insight for the composition optimization and future design of layered Ni-rich cathode materials.

Sb nanoparticles embedded uniformly on the surface of porous carbon fibres for high-efficiency sodium storage.

Sb nanoparticles (∼50 nm) are embedded uniformly on the surface of carbon fibers (Sb NPs-SCFs) without scattered Sb NPs. The Sb NPs-CNFs anode exhibits excellent sodium storage, delivering a second cycle discharge capacity of 455.7 mA h g-1 at 1.0 A g-1 and a stable capacity of 381.9 mA h g-1 after 200 cycles, achieving a notable retention of 83.8%.

The Effects of Small Amounts of Cobalt in LiNi1-XCoxO2 on Lithium Diffusion

Lithium-ion batteries with Co-free Ni-rich cathodes have attracted interest due to lower cost and supply chain issues compared to cobalt-containing cathodes1. However, cobalt is thought to provide some benefits in cycling stability and rate performance. In this work, cobalt substitution for nickel in the positive electrode material LiNi1-xCoxO2 at 0 ≤ x ≤ 0.10 is systematically investigated to determine the impact of Co and material synthesis conditions on Li diffusivity, measured using the Atlung Method for Intercalant Diffusion (AMID)2,3 in coin cells vs Li metal negative electrodes. Cobalt was found to have no impact on Li diffusivity in the intermediate voltage range (4.2 V to 3.7 V), while cation mixing (%Ni in Li layer) was found to have a strong correlation to slow Li diffusivity. At high voltage (4.3 V to 4.2 V), 0 to 10% cobalt incrementally suppresses the H2-H3 phase transition4,5 enabling significantly faster lithium diffusion. Cation mixing can be minimized through synthesis conditions, improving Li diffusivity for the low and intermediate voltage regions, without using Co. In summary, with optimal positive electrode material synthesis conditions and limiting cell upper cutoff voltage to 4.2 V, Co-free Ni-rich materials can be made with similar rate performance as 10% Cobalt-containing materials. Additionally, cobalt was found to have minimal impact on the following material properties: crystallinity of LiNi1-xCoxO2, surface impurities, particle size, and electronic conductivity. Cobalt substituted for nickel from 0% to 10% was found to decrease first cycle discharge capacity in the voltage range between 3.0 V and 4.3 V and improve capacity retention in coin cell cycling vs Li metal negative electrodes. The capacity retention improvement is most likely due to the suppression of the H2-H3 phase transition as Co is added5. Figure 1. (a), (b) shows %Ni in Li layer vs Cobalt content, obtained from powder XRD Rietveld refinement from a series of LiNi1-xCoxO2 materials. (a), (b) were synthesized under two different O2 flow velocities, both at 700oC for 20 hours, with a Li:TM ratio of 1.02:1. (c), (d) Show the lithium chemical diffusion coefficient vs cell voltage for the materials from (a), (b), respectively, measured using the Atlung Method for Intercalant Diffusion (AMID), in coin cells at 30oC. The protocol consists of 2C to C/160-rate discharge steps per voltage interval (0.1V), with OCV relaxation in between discharge steps. Figure 1

An Improved Lithium-Sulfur Battery By Using Porous Carbon As the Sulfur Template

As global demand for electric vehicles (EVs) continues to rise, the rechargeable battery of high-energy density is actively researched. Lithium-ion batteries (LIBs) have been widely used in the electric vehicles (EVs) and have been leading the EVs market. However, LIBs have reached their limits due to their practical low-capacity and high-cost. Therefore, novel strategy is required to solve the problem of the LIBs.Lithium-sulfur (Li-S) batteries attract attention because of high theoretical capacity (1675 mAh/g) and high energy density (2600 Wh/kg). Moreover, sulfur as electrode material is abundant and inexpensive. However, the sulfur-based batteries have serious disadvantages, which is the shuttle of intermediate polysulfides (Li2Sn, 2<n≤8), and low conductivity, result in poor cycle stability and low discharge capacity [1,2].Therefore, in this study, the sulfur electrode is fabricated by impregnating sulfur into three-dimensional porous carbon. The porous structure suppressed the dissolution/shuttle of sulfur species and improved the cycling stability and discharge capacity. Moreover, three types of porous carbon templated of activated carbon cloth, activated carbon felt, and porous carbon foam were compared on electrochemical performances.Reference Jimin Yun, 2023, High Loading Sulfur Cathode with Three-dimensional Porous Current Collector for Lithium-Sulfur Battery, Department of Materials Engineering and Convergence Technology, Gyeongsang National University, P.11, p.14Kimin Park, 2022, Design od metal phosphate based electrodes for high-performance Li-Ion & Li-S battery, Department of materials science and engineering seoul national university, P.1

Enabling high performance all-solid-state thin films microbatteries with silicon oxycarbide/lithium-metal composites anodes

All-solid-state thin films micro-batteries (ASSTFBs) integrating thin-films technologies with solid-electrolytes are regarded as promising power sources that can inherently alleviate safety issues for the miniaturized devices for internet of things (IoT). However, poor interfacial compatibility and low ionic conductivity induced by using of solid-state electrolytes urgently demand new development of novel materials and preparation technologies. In this work, novel silicon oxycarbide/lithium-metal composites anodes for ASSTFBs of IoT micro-devices are prepared by magnetron sputtering, and the electrochemical performances are systematically investigated via experiments and first-principles. The thin films batteries systems present high first cycle discharge capacities up to 104.15 mAh/g. The sample with the highest carbon content of SiCO shows superior coulomb efficiency of 97 % after 40 cycles and retention rates of 73.29 % at 0.1 C, and sample with the optimal feature size of free carbon presents the most outstanding comprehensive electrochemical properties. First-principles calculations reveal that the optimal LiPON/SiCO interface presents the highest adhesion strength and superior lithium diffusion properties with the lowest energy barrier for lithium diffusion. The relatively larger free carbon network limit volume expansion upon insertion of lithium, and silicon tetrahedral in SiCO show large lithium storage density, leads to improved cycling performance and high lithium capacity of the system.

Benchmarking the electrochemical parameters of the LiNi0.8Mn0.1Co0.1O2 positive electrode material for Li-ion batteries

The layered oxide LiNi0.8Mn0.1Co0.1O2 (NMC811, NCM811) is of utmost technological importance as a positive electrode (cathode) material for the forthcoming generation of Li-ion batteries. In this contribution, we have collected 548 research articles comprising >950 records on the electrochemical properties of NMC811 as a cathode material in half-cells with metallic Li counter electrode. The analysis of distribution histograms provided statistically-relevant values of such key characteristics of NMC811 as the first cycle discharge capacity and Coulombic efficiency, discharge capacities at different upper cut-off voltages, capacity fade and capacity retention at the 0.1C–5C current densities. We derived equations describing the relationships between discharge capacity and upper cut-off voltage, Ni content in the LiNixMnyCozO2 compositions in vicinity of NMC811, antisite disorder, and the C-rate. Additionally, the distribution histograms were used for a qualitative comparison between various groups of NMC811 materials, such as benchmarks in various optimizations vs obtained in course of synthesis development, lab-made vs commercial, polycrystalline vs single-crystal. The results of this analysis provide justified values to be used as benchmarks in further works related to optimizing and improving NMC811 and related materials, eliminating random picking up from a huge pool of published data.

Heme-Based Composites as Cathode Catalysts for Lithium-Oxygen Batteries and Analysis of the Reaction Mechanism

Despite the high theoretical energy density of lithium-oxygen (Li-O2) batteries, the charge/discharge efficiency is unsatisfactory. To overcome this critical problem, we synthesized heme-graphene composites (HEME-GO) as catalysts for Li-O2 batteries. The introduction of graphene produced π-π interactions with the heme matrix, resulting in a composite with enhanced ORR/OER catalytic activity. The free energy diagram of the redox reaction was calculated using density functional theory (DFT) for HEME-GO based on the four-electron reaction pathway, and it was demonstrated that HEME-GO has the lowest ORR overpotential (0.67 V) and OER overpotential (0.53 V). The catalytic mechanism of HEME-GO was also quantitatively described by calculating the adsorption energy of intermediates in the rate determining step (RDS). In addition, the Li-O2 batteries with the composite catalyst exhibited better cycling performance, discharge capacity (7770 mAh g−1), and lower overpotential due to the ability of heme to scavenge superoxide radicals and thus protect the electrode. The results in this paper contribute to the understanding of the redox process of Li-O2 batteries for organic systems and suggest innovative ideas for the design of environmentally friendly batteries.

Regenerated Ni-Rich Cathode Materials from Spent Li-Ion Batteries by a Closed Loop Process

The demand for rechargeable lithium-ion batteries (LIBs) has increased exponentially since they were first commercialized by Sony in 1991.[1] Due to the high energy density and excellent cycle stability, LIBs have been widespread utilized in electric vehicles and other applications. However, the lifespan of LIBs is limited. Thus, tons of spent LIBs are generated during the recent decades. More importantly, the price of raw materials, including lithium and cobalt salts, for producing LIBs grows significantly.[2, 3] Therefore, recycling these End-of-Life LIBs becomes a non-negligible part in the whole manufacturing process and hydrometallurgical process is the most common recycling method. Here, our group has demonstrated a closed loop recycling process, combining inorganic acid etching and coprecipitation reaction, to produce regenerated Ni-rich cathode materials. The regenerated LiNi0.83Mn0.06Co0.11O2 shows excellent performance: the first cycle discharge capacity is 214.1mAh/g at 0.05C in the voltage range of 2.8 - 4.3V and the initial columbic efficiency is 90.9%. The performance of our regenerated cathode materials is comparable to commercial cathode materials. In order to further optimize the properties of the regenerated LiNi0.83Mn0.06Co0.11O2, different elements, like Al, with various doping or coating methods will be utilized. Manthiram A. A reflection on lithium-ion battery cathode chemistry. Nature Communications 2020; 11(1):1550.Li W, Lee S, Manthiram A. High‐Nickel NMA: A Cobalt‐Free Alternative to NMC and NCA Cathodes for Lithium‐Ion Batteries. Advanced materials (Weinheim) 2020; 32(33):2002718-n/a.Hou J, Ma X, Fu J, Vanaphuti P, Yao Z, Liu Y, et al. A green closed-loop process for selective recycling of lithium from spent lithium-ion batteries. Green Chemistry 2022; 24(18):7049-7060.

The Effects of Small Amounts of Cobalt in LiNi1−xCoxO2 on Lithium-ion Diffusion

Cobalt substitution for nickel in the positive electrode material LiNi1-xCoxO2 at 0 ≤ x ≤ 0.10 is investigated to determine the impact of cobalt on Li diffusivity, measured using the Atlung Method for Intercalant Diffusion (AMID) in coin cells. Cobalt was found to have little to no impact on Li diffusivity in the intermediate voltage range (4.2 V to 3.7 V). At high voltage (4.3 V to 4.2 V), 0 to 10% cobalt incrementally suppresses the H2–H3 phase transition and enables faster lithium diffusion. Additionally, at low voltage in the kinetic hindrance region (3.7 V to 3.0 V) cobalt can improve lithium diffusion by reducing cation mixing (nickel in the lithium layer). However, cation mixing can also be minimized through synthesis conditions, improving diffusivity without using cobalt. Cobalt was found to have minimal impact on the following material properties of LiNi1-xCoxO2: crystallinity, surface impurities, particle size, and electronic conductivity. Cobalt substituted for nickel from 0% to 10% was found to decrease first cycle discharge capacity in the voltage range between 4.3 V to 3.0 V and improve capacity retention in coin cell cycling vs Li metal negative electrodes. The latter impact is most likely due to the suppression of the H2–H3 phase transition as Co is added.

Predicting future capacity of lithium-ion batteries using transfer learning method

Lithium-ion (Li-ion) batteries have numerous applications, such as electric vehicles, power tools, medical devices, drones, satellites, and utility-scale storage. Remaining useful life (RUL) prediction is a challenging task due to the highly nonlinear degradation behavior and prediction of batteries dealing with unknown future data. Online RUL prediction for Li-ion batteries plays an important role in proper battery health management. To improve the prediction accuracy of RUL, we propose a novel hybrid method based on transfer learning to predict the future capacity of Li-ion batteries. The proposed method consists of integrating an ensemble empirical mode decomposition algorithm, a support vector regression model, and a bidirectional long short-term memory with attention mechanism model to predict the state of health (SOH), where SOH is the battery cycle life and discharge capacity measured in number of cycles. In addition, we also consider keen-onset effects. The performance of RUL predictions using different starting RUL prediction points is compared with experiments. The proposed method shows that the larger the cycle number of the RUL prediction starting point, the more accurate the RUL prediction results. The relative error values for the three different charging policy target batteries using the proposed method are 6.96 %, 0.6 %, and 6.25 %, respectively. The proposed method is effective for predicting the future capacity of Li-ion batteries and can be applied to predictive maintenance.