Lithium Manganese Oxide Batteries Research Articles

Environmental performance of integrated solar flow battery systems

Integrated solar flow batteries (SFBs) are developed from a novel technology combining the functions of electricity generation and storage in one integrated device. Despite being in their infancy, their high efficiency, compact design, and reduced electronics are widely established. However, we know little about their environmental performance. Here, we present this lab-scale technology's first detailed life cycle assessment, specifically of one using a perovskite/silicon tandem photoelectrode. We also compared the environmental performance of the integrated SFB with an established competitor: a photovoltaic panel using the same tandem, coupled with a lithium manganese oxide battery. We found that, on average, ∼59% of the environmental impacts are from the electrolytes, 23% from the structure, and 18% from the PV component of the SFB. Our results showed that by replacing the Teflon and polyether ether ketone materials used in the structure of this SFB, we could reduce ozone depletion and global warming potential impacts by 85% and 36% respectively. Extending the lifetime of the electrolytes can further improve this SFB's environmental performance.

Exceptional energy absorption characteristics and compressive resilience of functional carbon foams scalably and sustainably derived from additively manufactured kraft paper

To incentivize carbon sequestration activities, kraft paper, a renewable and recyclable bioproduct that is already manufactured at scale, is proposed as feedstock for producing economically viable carbon materials. The paper was first additively manufactured into 3D open cell honeycombs and closed cell plate lattices using a sheet lamination process before being pyrolyzed into paper-derived architected carbon foams (PDACFs). In the isostress orientation, PDACFs displayed low moduli, high elastic strains (~ 30–40%) and a compressive resilience similar to graphene aerogels, but at stresses up to ~ 3 orders of magnitude higher, despite the brittle nature of the carbonized fibers. In the isostrain orientation, PDACFs exhibited better moduli (~ 1 MPa – 1 GPa), which were comparable to conventional carbon foams, and smaller elastic strains (~ 5–10%). Failure in isostrain orientation proceeded by fracture propagation through and/ or between the layers while cracks in the isostress orientation extended mainly across the layers. The strength of the PDACFs (~ 0.2 – 14 MPa) was similar in both orientations, however, likely because both interlayer and intralayer failure onset involved microscopic fractures initiating and propagating through a multitude of carbonized fiber interfaces. Notably, Honeycombs and Plate Simple Cubic PDACFs exhibited a combination of strength (> 3 MPa) and energy absorption (> 1 MJ/m 3 ; > 1 kJ/kg) not found in porous carbon materials previously, suggesting that the hierarchical arrangement of carbonized fibers within a macroscopic lattice architecture is better for dissipating energy than the tetrakaidecahedron microstructure commonly found in foams. Furthermore, as an electrode in a Li-ion battery, the carbonized cellulose making up PDACFs showed reversible specific capacities of 65–140 mAh/g at a specific current of 10 mA/g for 300 cycles, which is comparable to that of commercial lithium manganese oxide batteries and graphitic anodes derived from non-renewable polymer foams. Closed cell and open cell carbon lattices, realized through a novel additive manufacturing method and pyrolysis of eco-friendly kraft paper, displayed energy storage properties, as well as combinations of compressive resilience, energy absorption and strength unmatched by current porous carbon materials. • Novel ERASL technique was introduced to fabricate closed cell plate lattices and open cell honeycomb lattices. • Lattices were made from kraft paper and pyrolyzed into Paper-Derived Architected Carbon Foams (PDACFs). • PDACFs exhibited an unprecedented combination of strength (> 3MPa) and energy absorption (> 1 MJ/m 3 and > 1 kJ/kg). • PDACFs displayed high compressive resilience similar to graphene aerogels, but at stresses up to 1000X higher. • As a Li-ion battery anode, PDACF showed reversible specific capacities of 65 – 140 mAh/g for 300 cycles.

A reliable estimation method for mining lithium-ion battery

Power battery SOC (state of charge, SOC) is one of the important decision-making factors of energy management. Accurate estimation plays an important role in optimizing vehicle energy management and improving the utilization of power battery energy. The key to accurate estimation of SOC is to determine circuit model parameters and estimation methods. The research object of this article is lithium manganese oxide battery for mining (LiMn2O4). The experiments of multiplying power, temperature and HPPC (hybrid pulse power characteristic, HPPC) are carried out. A self-tuning calculation method of dynamic system is proposed, and the dynamic self-tuning model based on second-order RC is established. At the same time, in view of the shortcoming that the UKF (Unscented Kalman Filter, UKF) algorithm cannot estimate the noise in real time, In order to improve the accuracy of battery SOC estimation, an adaptive square root unscented Kalman filter (ASR-UKF) algorithm is proposed, which can make the noise statistical characteristics follow the estimation results for adaptive adjustment. Finally, the constant current and dynamic conditions are tested. The results show that the maximum change rate of model parameters with magnification is 76%, and the maximum change rate with temperature is 73.7%. The analysis of dynamic characteristics is a key factor to improve the accuracy of SOC estimation; ASR-UKF Compared with the UKF algorithm, the error is reduced by 78% under constant current conditions and 85.7% under dynamic conditions. The reliability and real-time performance of the algorithm can be obtained by comparing the simulation data with the actual data. The conclusions of this paper can be used as a theoretical basis, which can be used for model analysis of lithium batteries for mining and estimation of internal state variables.

Uncovering the in-use metal stocks and implied recycling potential in electric vehicle batteries considering cascaded use: a case study of China.

With the rapid promotion of new energy vehicles, in-use electric vehicle batteries (EVBs) are becoming an important component of urban mining. This paper analyzed the metal stocks in EVBs in China from 2009 to 2019 using a bottom-up method, which focused on the in-use stock of seven main metals, namely, nickel, cobalt, manganese, lithium, copper, aluminum, and iron, in primary use stage and secondary use stage of three EVB types, namely, lithium nickel manganese cobalt oxide battery (NMC), lithium iron phosphate battery (LFP), and lithium manganese oxide battery (LMO). It was found that the rapid development of electric vehicles (EVs) contributed to a dramatic increase in in-use metal stocks from 0.7 kt in 2009 to 1.1 Mt in 2019. To assess the increase, three scenarios simulating metal stocks in EVBs from 2020 to 2030 were analyzed, namely, baseline, NMC-dominated, and LFP-dominated, and results indicated that metal stocks will reach 20.6 Mt, 23.2 Mt, and 17.9 Mt, respectively, by 2030. Across the scenarios there is little proportional difference in metal stocks between the two use stages. The proportion of the three EVB types correlates to the development trend of EVB technology under each corresponding scenario. Besides, the in-use metal stocks in EVBs have high implied recycling potential and environmental benefit. The recycling potential of these seven metals is 1.0 Mt in 2019, and it will reach 20.0 Mt, 22.6 Mt, and 17.4 Mt, respectively, in 2030 under the three scenarios. The results reveal the current status and evolution characteristics of metal stocks in EVBs in China, and provide data for material flow analysis and life cycle management of EVBs.

Effect of Activated Carbon from Rice Husk on the Rate Performance of Lithium Manganese Oxide Battery

Effect of Activated Carbon from Rice Husk on the Rate Performance of Lithium Manganese Oxide Battery

Li-Ion Battery-Flywheel Hybrid Storage System: Countering Battery Aging During a Grid Frequency Regulation Service

In this paper, a hybrid storage system solution consisting of flywheels and batteries with a Lithium-manganese oxide cathode and a graphite anode is proposed, for supporting the electrical network primary frequency regulation. The aim of the paper is to investigate the benefits of flywheels in mitigation of the accelerating aging that li-ion batteries suffer during the grid frequency regulation operation. For this purpose, experimental aging tests have been performed on a lithium-manganese oxide battery module and an electrical battery model which takes into account the battery aging has been developed in a Simulink environment. Then, a flywheel electrical model has been implemented, taking into account the thermal and the electromechanical phenomena governing the electrical power exchange. This more complete model of a hybrid storage system enables us to simulate the same aging cycles of the battery-based storage system and to compare the performances of the latter with the hybrid storage system. The simulation results suggest that suitable control of the power shared between the batteries and the flywheels could effectively help in countering Li-ion battery accelerated aging due to the grid frequency regulation service.

Chemical composition and formation mechanisms in the cathode-electrolyte interface layer of lithium manganese oxide batteries from reactive force field (ReaxFF) based molecular dynamics

Lithium manganese oxide (LiMn2O4) is a principal cathode material for high power and high energy density electrochemical storage on account of its low cost, non-toxicity, and ease of preparation relative to other cathode materials. However, there are well-documented problems with capacity fade of lithium ion batteries containing LiMn2O4. Experimental observations indicate that the manganese content of the electrolyte increases as an electrochemical cell containing LiMn2O4 ages, suggesting that active material loss by dissolution of divalent manganese from the LiMn2O4 surface is the primary reason for reduced cell life in LiMn2O4 batteries. To improve the retention of manganese in the active material, it is key to understand the reactions that occur at the cathode surface. Although a thin layer of electrolyte decomposition products is known to form at the cathode surface, the speciation and reaction mechanisms of Mn2+ in this interface layer are not yet well understood. To bridge this knowledge gap, reactive force field (ReaxFF) based molecular dynamics was applied to investigate the reactions occurring at the LiMn2O4 cathode surface and the mechanisms that lead to manganese dissolution. The ReaxFFMD simulations reveal that the cathode-electrolyte interface layer is composed of oxidation products of electrolyte solvent molecules including aldehydes, esters, alcohols, polycarbonates, and organic radicals. The oxidation reaction pathways for the electrolyte solvent molecules involve the formation of surface hydroxyl species that react with exposed manganese atoms on the cathode surface. The presence of hydrogen fluoride (HF) induces formation of inorganic metal fluorides and surface hydroxyl species. Reaction products predicted by ReaxFF-based MD are in agreement with experimentally identified cathode-electrolyte interface compounds. An overall cathode-electrolyte interface reaction scheme is proposed based on the molecular simulation results.

Reduced-Order Electrochemical Model-Based SOC Observer With Output Model Uncertainty Estimation

As an integral part of energy storage systems, Li-ion batteries require extensive management to guarantee their safe and efficient operation. Estimation of the remaining energy capability of the battery, usually expressed in terms of state of charge (SOC), plays an important role in any battery-powered application. Electrochemical model-based estimation techniques have proven very attractive for this purpose due to the additional information they provide regarding the internal battery operating conditions. A modified reduced-order model based on the single particle approximation of the electrochemical model, suitable for the real-time implementation of SOC estimation, is employed in this paper. This model, while maintaining some of the physical insights about the battery operation, provides a basis for an output-injection observer design to estimate the SOC. Output model uncertainties, originating primarily from the electrolyte-phase potential difference approximation and encountered mainly at higher discharge rates, are handled by incorporating an adaptation algorithm in the observer. Therefore, the proposed method, while being suitable for online implementation, provides an electrochemical model-based solution for battery SOC estimation over a wide range of operations. System stability and the robustness of the estimates given measurement noise are proved analytically using Lyapunov stability. Finally, accurate performance of the proposed SOC estimation technique is illustrated using simulation data obtained from a full-order electrochemical model of a lithium manganese oxide battery.

Chemical Composition and Formation Reactions in the Cathode-Electrolyte Interface Layer of Lithium Manganese Oxide Batteries from Reactive Force Field (ReaxFF) Molecular Dynamics

Lithium ion batteries have great potential to revolutionize the transportation sector as energy storage media for electric mobility. Among the various lithium metal oxides that have been used, or proposed for use, as cathode active materials, lithium manganese oxide (LiMn2O4) is the primary cathode material presently exploited for automotive applications, on account of its low cost, low toxicity, and simple preparation process. There are, however, well-documented problems with LiMn2O4, the most critical of which is capacity fade due to active material loss. The dissolution of divalent manganese from the surface of the cathode into the electrolyte leads to a progressive decrease in the cathode material available for lithium intercalation. Deposition of dissolved manganese on the anode decreases the lithium content of the anode, further decreasing the overall cell capacity. Experimental observations indicate that the manganese content of the electrolyte increases as the cell ages, suggesting that cathode material loss is the primary reason for reduced cell life in a LiMn2O4 battery. A key to improving the retention of manganese used as cathode material is to understand the reactions that occur at the cathode surface. Although Mn2+ has been experimentally detected in the electrolyte of LiMn2O4 cells, its speciation and reaction mechanisms are not yet well understood. Manganese dissolution is more pronounced in the presence of fluorinated electrolyte salts such as LiPF6, linking fluorine in the electrolyte as a putative trigger for manganese dissolution. Tunneling electron microscopy imaging has shown the presence of a layer of electrolyte decomposition products at the cathode surface, but no experimental composition analysis has been possible due to the thinness and delicate structure of this layer. Fluorinated electrolyte additives such as fluoroethylene carbonate (FEC) are used in commercial cells to enable formation of a more stable anode-electrolyte interface layer, thereby improving battery performance. The impact of this new source of fluorine on manganese dissolution and battery life has not yet been explored. To bridge this knowledge gap, molecular modeling and density functional theory methods were applied to investigate the reactions occurring at the LiMn2O4 cathode surface, the effects of fluorinated electrolyte additives on the cathode-electrolyte interface layer, and the mechanisms of manganese dissolution. Specifically, a reactive force field (ReaxFF) was developed to conduct molecular dynamics (MD) simulations of these electrochemical cells. Reactive force fields can simulate the formation and dissociation of chemical bonds, and thereby help to disclose the dynamic surface reaction chemistry of the cathode. The reactive force field developed for manganese was used to investigate the formation of the cathodeelectrolyte interface layer in electrochemical cells with a LiMn2O4 cathode, ethylene carbonate / dimethyl carbonate electrolyte, LiPF6 salt, and 5% FEC additive. The MD simulations reveal that the electrolyte solvent molecules undergo oxidation by taking up oxygen atoms from the bulk cathode. The cathodeelectrolyte interface layer was found to contain aldehydes, polycarbonates and organic radicals. The oxidation reaction pathways for all the electrolyte solvent molecules reveal the formation of surface hydroxyl species. The removal of oxygen from the cathode lattice exposes manganese atoms to the bulk electrolyte and the hydroxyl molecules are very likely to result in acid formation on the cathode surface, these two processes together result in manganese dissolution from the cathode into the electrolyte. The chemical composition of the cathode surface interface layer with and without the electrolyte additive FEC, and the role of FEC in Mn dissolution were investigated. Simulation results generated by ReaxFF-based MD were found to be in agreement with the experimentally identified cathode-electrolyte interface compounds. Based on the Reax-FF MD simulations, the catalytic properties of manganese oxides lead to oxidative decomposition of electrolyte solvents resulting in consumption of cathode oxygen and dissolution of manganese atoms. Figure 1

Lithium-Ion Battery Energy Storage Systems for Grid Applications

The use of storage devices to support grid functions is seen as a viable option to meet an increasing electricity demand. Simulations performed will provide a look into the sustainability and life of a lithium-ion battery in continuous operation that can be used to support on-grid services. Specifically, COMSOL Multiphysics will be used to model a lithium manganese oxide battery and illustrate the capacity fade, solid-electrolyte interphase (SEI) formation leading to potential drop and electrolyte potential drop in the battery. These simulations will provide insight into continuous cycling phenomena of charging and discharging a battery.