The Battery Component Readiness Level (BC-RL) framework: A technology-specific development framework

Government investment constitutes a large portion of overall investment in research and development of lithium-ion batteries (LIBs) and other future battery technologies with the goal of electrifying the transportation sector and so removing a major source of global greenhouse gas emissions. Poor investments, however, can result in taxpayer funding losses and political backlash, making clear communication and informed decision-making critical. This manuscript presents the Battery Component Readiness Level scale, an overhauled version of the Technology Readiness Level (TRL) scale currently utilized by the EU for innovation programs that has been customized for use in battery technology development. It retains the structure of the EU TRL scale while adding in-depth description of technology-specific development as well as discussion of aspects such as manufacturability and cost that are necessary to understand technological promise and risk. Its use by the EU and other parties involved in battery development can thus improve communication between all involved sectors, from government to academia to industry, and can aid in better-informed decision-making regarding investments. This can ultimately contribute to a more efficient electrification of the transportation sector and any other sectors where batteries display transformative potential

Impact of Degree of Graphitization, Surface Properties and Particle Size Distribution on Electrochemical Performance of Carbon Anodes for Potassium‐Ion Batteries

Carbons are considered as anode active materials in potassium ion batteries (PIBs). Here, the correlation between material properties of disordered (non-graphitic) and ordered graphitic carbons and their electrochemical performance in carbon || K metal cells is evaluated. First, carbons obtained from heat treatment of petroleum coke at temperatures from 800 to 2800 °C are analyzed regarding their microstructure and surface properties. Electrochemical performance metrics for K+ ion storage like specific capacity and Coulombic efficiency (CEff) are correlated with surface area, non-basal planes and microstructure properties, and compared to Li+ ion storage. For disordered carbons, the specific capacity can be clearly correlated with the defect surface area. For highly ordered graphitic carbons, the degree of graphitization strongly determines the specific capacity. The initial CEff of graphitic carbons shows a strong correlation with basal and non-basal planes. Second, kinetic limitations of ordered graphitic carbons are re-evaluated by analyzing commercial graphites regarding particle size and surface properties. A clear correlation between particle size, surface area and well-known challenges of graphitic carbons in terms of low-rate capability and voltage hysteresis is observed. This work emphasizes the importance of bulk and surface material properties for K+ ion storage and gives important insights for future particle design of promising carbon anodes for PIB cells

Scalable Synthesis of MAX Phase Precursors toward Titanium-Based MXenes for Lithium-Ion Batteries

MXenes have emerged as one of the most interesting material classes, owing to their outstanding physical and chemical properties enabling the application in vastly different fields such as electrochemical energy storage (EES). MXenes are commonly synthesized by the use of their parent phase, i.e., MAX phases, where “M” corresponds to a transition metal, “A” to a group IV element, and “X” to carbon and/or nitrogen. As MXenes display characteristic pseudocapacitive behaviors in EES technologies, their use as a high-power material can be useful for many battery-like applications. Here, a comprehensive study on the synthesis and characterization of morphologically different titanium-based MXenes, i.e., Ti3C2 and Ti2C, and their use for lithium-ion batteries is presented. First, the successful synthesis of large batches (≈1 kg) of the MAX phases Ti3AlC2 and Ti2AlC is shown, and the underlying materials are characterized mainly by focusing on their structural properties and phase purity. Second, multi- and few-layered MXenes are successfully synthesized and characterized, especially toward their ever-present surface groups, influencing the electrochemical behavior to a large extent. Especially multi- and few-layered Ti3C2 are achieved, exhibiting almost no oxidation and similar content of surface groups. These attributes enable the precise comparison of the electrochemical behavior between morphologically different MXenes. Since the preparation method for few-layered MXenes is adapted to process both active materials in a “classical” electrode paste processing method, a better comparison between both materials is possible by avoiding macroscopic differences. Therefore, in a final step, the aforementioned electrochemical performance is evaluated to decipher the impact of the morphology difference of the titanium-based MXenes. Most importantly, the delamination leads to an increased non-diffusion-limited contribution to the overall pseudocapacity by enhancing the electrolyte access to the redox-active sites

Advanced Dual‐Ion Batteries with High‐Capacity Negative Electrodes Incorporating Black Phosphorus

Dual-graphite batteries (DGBs), being an all-graphite-electrode variation of dual-ion batteries (DIBs), have attracted great attention in recent years as a possible low-cost technology for stationary energy storage due to the utilization of inexpensive graphite as a positive electrode (cathode) material. However, DGBs suffer from a low specific energy limited by the capacity of both electrode materials. In this work, a composite of black phosphorus with carbon (BP-C) is introduced as negative electrode (anode) material for DIB full-cells for the first time. The electrochemical behavior of the graphite || BP-C DIB cells is then discussed in the context of DGBs and DIBs using alloying anodes. Mechanistic studies confirm the staging behavior for anion storage in the graphite positive electrode and the formation of lithiated phosphorus alloys in the negative electrode. BP-C containing full-cells demonstrate promising electrochemical performance with specific energies of up to 319 Wh kg–1 (related to masses of both electrode active materials) or 155 Wh kg–1 (related to masses of electrode active materials and active salt), and high Coulombic efficiency. This work provides highly relevant insights for the development of advanced high-energy and safe DIBs incorporating BP-C and other high-capacity alloying materials in their anodes

Understanding the Role of Commercial Separators and Their Reactivity toward LiPF 6 on the Failure Mechanism of High‐Voltage NCM523 || Graphite Lithium Ion Cells

NCM523 || graphite lithium ion cells operated at 4.5 V are prone to an early “rollover” failure, due to electrode cross-talk, that is, transition metal (TM = Mn, Ni, and Co) dissolution from NCM523 and deposition at graphite, subsequent formation of Li metal dendrites, and, in the worst case, generation of (micro-)short-circuits by dendrites growing to the cathode. Here, the impact of different separators on the high-voltage performance of NCM523 || graphite cells is elucidated focusing on the separators’ structural properties (e.g., membrane vs fiber) and their reactivity toward LiPF6 (e.g., ceramic-coated separators). First, the separator architecture has a major impact on cycle life. Fiber-structured separators can prevent the “rollover” failure by a more homogeneous deposition of TMs and formation of Li metal dendrites, thus, hindering penetration of dendrites to the cathode. In contrast, porous membrane-structured separators cannot prevent the cell failure due to inhomogeneous TM deposits/Li metal dendrites. Second, it is demonstrated that different types of ceramic-coated separators (Boehmite (γ-AlO(OH)) vs α-Al2O3) exhibit different reactivities toward LiPF6. While α-Al2O3 shows a minor reactivity toward LiPF6, the γ-AlO(OH) coating leads to in situ formation of the beneficial difluorophosphate anion in high amounts due the high reactivity toward LiPF6 decomposition, which significantly improves cycle life