Recent insights into the electrochemical behavior of blended lithium insertion cathodes: A review

An Integrated Model to Conduct Multi-Criteria Technology Assessments: The Case of Electric Vehicle Batteries

The large-scale adoption of low-carbon technologies can result in trade-offs between technical, socio-economic, and environmental aspects. To assess such trade-offs, discipline-specific models typically used in isolation need to be integrated to support decisions. Integrated modeling approaches, however, usually remain at the conceptual level, and operationalization efforts are lacking. Here, we propose an integrated model and framework to guide the assessment and engineering of technical, socio-economic, and environmental aspects of low-carbon technologies. The framework was tested with a case study of design strategies aimed to improve the material sustainability of electric vehicle batteries. The integrated model assesses the trade-offs between the costs, emissions, material criticality, and energy density of 20,736 unique material design options. The results show clear conflicts between energy density and the other indicators: i.e., energy density is reduced by more than 20% when the costs, emissions, or material criticality objectives are optimized. Finding optimal battery designs that balance between these objectives remains difficult but is essential to establishing a sustainable battery system. The results exemplify how the integrated model can be used as a decision support tool for researchers, companies, and policy makers to optimize low-carbon technology designs from various perspectives.

Electrochemical Performance of Graphene Oxide/Black Arsenic Phosphorus/Carbon Nanotubes as Anode Material for LIBs

As a new two-dimensional material, black arsenic phosphorus (B-AsP) has emerged as a promising electrode for lithium-ion batteries (LIBs) due to its large theoretical capacity and ability to absorb large amounts of Li atoms. However, the poor electronic conductivity and large volume expansion during the lithiation/delithiation process have largely impeded the development of B-AsP electrodes. In this study, graphene oxide (GO)/B-AsP/carbon nanotubes (CNTs) with remarkable lithium-storage property were fabricated via CVD and ultrasound-assisted method. The electrochemical behavior of the GO/B-AsP/CNTs was investigated as an anode in lithium-ion batteries. From the results, as a new-type anode for LIBs, GO/B-AsP/CNTs composite demonstrated a stable capacity of 1286 and 339 mA h g⁻¹ at the current density of 0.1 and 1 A g⁻¹, respectively. The capacity of GO/B-AsP/CNTs was 693 mA h g⁻¹ after 50 cycles, resulting in capacity retention of almost 86%. In addition, the stable P-C and As-C bonds were formed between B-AsP, GO, and CNTs. Thus, volume expansion of B-AsP was alleviated and the capacity was increased due to the confining effect of GO and CNTs.

Electrochemical Performance of Thick-Film Li(Ni0.6Mn0.2Co0.2)O2 Cathode with Hierarchic Structures and Laser Ablation

The electrochemical performance of lithium-ion batteries is directly influenced by type of active material as well as its morphology. In order to evaluate the impact of particle morphology in thick-film electrodes, Li(Ni_0.6Mn_0.2Co_0.2)O₂ (NMC 622) cathodes with bilayer structure consisting of two different particle sizes were manufactured and electrochemically characterized in coin cells design. The hierarchical thick-film electrodes were generated by multiple casting using NMC 622 (TA) with small particle size of 6.7 µm and NMC 622 (BA) with large particle size of 12.8 µm. Besides, reference electrodes with one type of active material as well as with two type of materials established during mixing process (BT) were manufactured. The total film thickness of all hierarchical composite electrodes were kept constant at 150 µm, while the thicknesses of TA and BA were set at 1:2, 1:1, and 2:1. Meanwhile, three kinds of thin-film cathodes with 70 µm were applied to represent the state-of-the-art approach. Subsequently, ultrafast laser ablation was applied to generate groove structures inside the electrodes. The results demonstrate that cells with thin-film or thick-film cathode only containing TA, cells with bilayer electrode containing TBA 1:2, and cells with laser-structured electrodes show higher capacity at C/2 to 5C, respectively.

Interplay between electrochemical reactions and mechanical responses in silicon-graphite anodes and its impact on degradation

Durability of high-energy throughput batteries is a prerequisite for electric vehicles to penetrate the market. Despite remarkable progresses in silicon anodes with high energy densities, rapid capacity fading of full cells with silicon-graphite anodes limits their use. In this work, we unveil degradation mechanisms such as Li⁺ crosstalk between silicon and graphite, consequent Li⁺ accumulation in silicon, and capacity depression of graphite due to silicon expansion. The active material properties, i.e. silicon particle size and graphite hardness, are then modified based on these results to reduce Li⁺ accumulation in silicon and the subsequent degradation of the active materials in the anode. Finally, the cycling performance is tailored by designing electrodes to regulate Li⁺ crosstalk. The resultant full cell with an areal capacity of 6 mAh cm^-2 has a cycle life of >750 cycles the volumetric energy density of 800 Wh L^-1 in a commercial cell format.

Ternary Cathode Blend Electrodes for Environmentally Friendly Lithium-Ion Batteries

The combination of two active materials into one positive electrode of a lithium-ion battery is an uncomplicated and cost-effective way to combine the advantages of different active materials while reducing the disadvantages of each material. In this work, the concept of binary blends is extended to ternary compositions. The combination of three different active materials provides high versatility in designing the properties of an electrode. Therefore, the unique properties of a layered oxide, phospho-olivine, and spinel type material are mixed to design a high-energy cathode with improved environmental friendliness. Four different compositions of blend electrodes are investigated, each with individual benefits. Synergistic effects improved the rate capability, power density, thermal and chemical stability simultaneously. The blend electrode consisting of 75 % NMC, 12.5 % LMFP and LMO provides similar energy and power density as a pure NMC electrode while economizing 25 % cobalt and nickel.