Engineering topics

Ahmed, Ridwan A.

Publications and source records attributed to Ahmed, Ridwan A..

3 records

DOE OSTI2024

Lithicone‐Protected Lithium Metal Anodes for Lithium Metal Batteries with Nickel‐Rich Cathode Materials

The high energy density advantage of lithium (Li) metal batteries (LMBs) makes them increasingly desirable; however, problems such as strong reactivity and dendrite growth of Li metal anode limit their practical uses. In this work, a novel Li‐containing glycerol (LiGL) or lithicone protection layer on a 50 μm thick Li metal anode is employed for improving the performance of LMBs. This LiGL layer was accurately deposited via a molecular layer deposition (MLD) process at 150 °C, using lithium tert‐butoxide and glycerol as precursors. The as‐formed LiGL coating layer is highly tunable in its thickness by simply adjusting MLD cycles and shows a good stability and outstanding ionic transport properties. The LiGL layer is found to effectively mitigate side reactions and enhance cycling stability in both symmetric cells and full cells. Specifically, the LMBs with LiGL@Li anode of 400 MLD cycles and LiNi 0.6 Mn 0.2 Co 0.2 O 2 cathode enable a capacity retention of ≈87%, much higher than ≈35% of the cells with bare Li after 200 cycles at a charge/discharge current density of 2.1 mA cm −2 . This work paves a feasible way for practical LMBs with improved capacity and stability through applying an innovative protection layer on Li metal anodes.

25 ENERGY STORAGE↗

DOE OSTI2024

Enhanced Electrochemical Performance of Disordered Rocksalt Cathodes in a Localized High‐Concentration Electrolyte

Abstract Lithium (Li)‐rich transition metal oxide cathodes with a cation disordered rock salt structure (DRX) are increasingly gaining popularity for advanced Li batteries as they offer high capacity and cost benefits over the commonly used layered Li transition metal oxide cathodes. However, the performance of DRX cathodes and their applications are limited by severe side reactions between the cathode and the state‐of‐the‐art carbonate‐based electrolytes at high voltage of 4.8 V, transition metal dissolution, and structural instability of the cathode particles. In this work, an advanced localized high‐concentration electrolyte (LHCE) is developed to form a stable cathode‐electrolyte interphase and mitigate structural instability of the Li 1.13 Mn 0.66 Ti 0.21 O 2 (LMTO) DRX during electrochemical cycling. Li||LMTO half cells with the LHCE demonstrate increased capacity, cycling stability, and superior rate capability compared with cells containing a conventional carbonate electrolyte. For instance, the Li||LMTO cells cycled in LHCE show a higher initial capacity of 205.2 mAh g −1 and a better capacity retention of 72.5% after 200 cycles at a current density of 20 mA g −1 than those with the conventional electrolyte (initial capacity of 187.7 mAh g −1 and capacity retention of 19.9%). This work paves the way to the development of practical DRX cathode‐based high‐energy Li batteries.

25 ENERGY STORAGE↗

DOE OSTI2024

Three-Dimensional Polymeric-Scaffold-Based Current Collector for a Lithium Metal Anode toward High-Energy-Density Batteries

Here, the practical applications of high-energy-density rechargeable lithium (Li) metal batteries (LMBs) have been impeded by the intrinsic issues of the Li metal anode (LMA) including high reactivity with electrolyte and dendritic formation. Conventional LMAs, which have the "hostless" feature consisting of a Li layer on a two-dimensional copper (Cu) foil as a current collector, led to additional loss in specific energy density, since Cu is a nonfaradaic heavy metal, bringing formidable areal capacity loss. To address these problems, a heat-treated three-dimensional-structured Cu-coated polyimide (HT-Cu@PI) membrane is designed and fabricated as a current collector. Benefiting from this unique material/structure, it enables not only better electrochemically deposited Li by a uniform/continuous Li-ion transport pathway but also a significant increase in the gravimetric/volumetric energy densities of LMBs by allowing more Li deposition in a fixed weight/volume. Therefore, this new LMA structure will accelerate the practical application of high-energy-density LMBs.

25 ENERGY STORAGE↗