Solomon Oyakhire is a PhD candidate in the department of chemical engineering. He received his BSc in chemical engineering at the University of Lagos in Nigeria before starting his PhD in chemical engineering as a Knight-Hennessy scholar. He is primarily interested in the scientific and economic facets required for accelerating the deployment of renewable energy technologies. Prior to Stanford, he carried out research on phase change materials applied in solar thermal heating systems at the University of Lagos and worked as a technology consultant at KPMG. By operating with frameworks that he gathered from research and consulting environs, he is currently working on developing high energy density batteries with practical applications in the grid and electric vehicles.
Revealing the Multifunctions of Li3N in the Suspension Electrolyte for Lithium Metal Batteries.
Inorganic-rich solid-electrolyte interphases (SEIs) on Li metal anodes improve the electrochemical performance of Li metal batteries (LMBs). Therefore, a fundamental understanding of the roles played by essential inorganic compounds in SEIs is critical to realizing and developing high-performance LMBs. Among the prevalent SEI inorganic compounds observed for Li metal anodes, Li3N is often found in the SEIs of high-performance LMBs. Herein, we elucidate new features of Li3N by utilizing a suspension electrolyte design that contributes to the improved electrochemical performance of the Li metal anode. Through empirical and computational studies, we show that Li3N guides Li electrodeposition along its surface, creates a weakly solvating environment by decreasing Li+-solvent coordination, induces organic-poor SEI on the Li metal anode, and facilitates Li+ transport in the electrolyte. Importantly, recognizing specific roles of SEI inorganics for Li metal anodes can serve as one of the rational guidelines to design and optimize SEIs through electrolyte engineering for LMBs.
View details for DOI 10.1021/acsnano.2c12470
View details for PubMedID 36700841
Investigating the Cyclability and Stability at the Interfaces of Composite Solid Electrolytes in Li Metal Batteries.
ACS applied materials & interfaces
Despite the fact that much work has been dedicated to finding the ideal additive for composite solid electrolytes (CSEs) for lithium-based solid-state batteries, little is known about the properties of a CSE that enable stable cycling with a lithium metal anode. In this work, we use three CSEs based on lithium nitride (Li3N), a fast lithium-ion conductor, and lithium hydroxide (LiOH) to investigate the properties and interfacial interactions that impact the cyclability of CSEs. We present a method for stabilizing Li3N with a shell of LiOH, and we incorporate Li3N, core-shell particles, and LiOH into CSEs using polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide. Through improved interfacial chemistry, CSEs with core-shell particles have superior electrochemical cycling performance compared to those with unprotected Li3N in symmetric Li-Li cells. This CSE features a high ionic conductivity of 0.66 mS cm-1 at 60 °C, a high critical current density of 1.2 mA cm-2, and a wide voltage window of 0-5.1 V. Full cells with the core-shell CSE and lithium iron phosphate cathodes exhibit stable cycling and high reversible specific capacities in cells as high as 2.5 mAh cm-2. We report that the improved ionic conductivity and amorphous PEO content have a limited effect on the solid-state electrolyte performance, while improving the electrolyte-Li metal anode interface is key to cycling longevity.
View details for DOI 10.1021/acsami.2c14677
View details for PubMedID 36416366
Correlating Kinetics to Cyclability Reveals Thermodynamic Origin of Lithium Anode Morphology in Liquid Electrolytes.
Journal of the American Chemical Society
The rechargeability of lithium metal batteries strongly depends on the electrolyte. The uniformity of the electroplated Li anode morphology underlies this dependence, so understanding the main drivers of uniform plating is critical for further electrolyte discovery. Here, we correlate electroplating kinetics with cyclability across several classes of electrolytes to reveal the mechanistic influence electrolytes have on morphology. Fast charge-transfer kinetics at fresh Li-electrolyte interfaces correlate well with uniform morphology and cyclability, whereas the resistance of Li+ transport through the solid electrolyte interphase (SEI) weakly correlates with cyclability. These trends contrast with the conventional thought that Li+ transport through the electrolyte or SEI is the main driver of morphological differences between classes of electrolytes. Relating these trends to Li+ solvation, Li nucleation, and the charge-transfer mechanism instead suggests that the Li/Li+ equilibrium potential and the surface energy─thermodynamic factors modulated by the strength of Li+ solvation─underlie electrolyte-dependent trends of Li morphology. Overall, this work provides an insight for discovering functional electrolytes, tuning kinetics in batteries, and explaining why weakly solvating fluorinated electrolytes favor uniform Li plating.
View details for DOI 10.1021/jacs.2c08182
View details for PubMedID 36318744
- An Interdigitated Li-Solid Polymer Electrolyte Framework for Interfacial Stable All-Solid-State Batteries ADVANCED ENERGY MATERIALS 2022
- An X-ray Photoelectron Spectroscopy Primer for Solid Electrolyte Interphase Characterization in Lithium Metal Anodes ACS ENERGY LETTERS 2022; 7 (8)
Electrical resistance of the current collector controls lithium morphology.
2022; 13 (1): 3986
The electrodeposition of low surface area lithium is critical to successful adoption of lithium metal batteries. Here, we discover the dependence of lithium metal morphology on electrical resistance of substrates, enabling us to design an alternative strategy for controlling lithium morphology and improving electrochemical performance. By modifying the current collector with atomic layer deposited conductive (ZnO, SnO2) and resistive (Al2O3) nanofilms, we show that conductive films promote the formation of high surface area lithium deposits, whereas highly resistive films promote the formation of lithium clusters of low surface area. We reveal an electrodeposition mechanism in which radial diffusion of electroactive species is promoted on resistive substrates, resulting in lateral growth of large (150m in diameter) planar lithium deposits. Using resistive substrates, similar lithium morphologies are formed in three distinct classes of electrolytes, resulting in up to ten-fold improvement in battery performance. Ultimately, we report anode-free pouch cells using the Al2O3-modified copper that maintain 60 % of their initial discharge capacity after 100 cycles, displaying the benefits of resistive substrates for controlling lithium electrodeposition.
View details for DOI 10.1038/s41467-022-31507-w
View details for PubMedID 35821247
- A Solution-Processable High-Modulus Crystalline Artificial Solid Electrolyte Interphase for Practical Lithium Metal Batteries ADVANCED ENERGY MATERIALS 2022
- Understanding and Utilizing Reactive Oxygen Reservoirs in Atomic Layer Deposition of Metal Oxides with Ozone CHEMISTRY OF MATERIALS 2022
- Methyl-methacrylate based aluminum hybrid film grown via three-precursor molecular layer deposition JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A 2022; 40 (2)
- Graphene coating on silicon anodes enabled by thermal surface modification for high-energy lithium-ion batteries MRS BULLETIN 2022
- Scalable, Ultrathin, and High-Temperature-Resistant Solid Polymer Electrolytes for Energy-Dense Lithium Metal Batteries ADVANCED ENERGY MATERIALS 2022
Suspension electrolyte with modified Li+ solvation environment for lithium metal batteries.
Designing a stable solid-electrolyte interphase on a Li anode is imperative to developing reliable Li metal batteries. Herein, we report a suspension electrolyte design that modifies the Li+ solvation environment in liquid electrolytes and creates inorganic-rich solid-electrolyte interphases on Li. Li2O nanoparticles suspended in liquid electrolytes were investigated as a proof of concept. Through theoretical and empirical analyses of Li2O suspension electrolytes, the roles played by Li2O in the liquid electrolyte and solid-electrolyte interphases of the Li anode are elucidated. Also, the suspension electrolyte design is applied in conventional and state-of-the-art high-performance electrolytes to demonstrate its applicability. Based on electrochemical analyses, improved Coulombic efficiency (up to ~99.7%), reduced Li nucleation overpotential, stabilized Li interphases and prolonged cycle life of anode-free cells (~70 cycles at 80% of initial capacity) were achieved with the suspension electrolytes. We expect this design principle and our findings to be expanded into developing electrolytes and solid-electrolyte interphases for Li metal batteries.
View details for DOI 10.1038/s41563-021-01172-3
View details for PubMedID 35039645
- Rational solvent molecule tuning for high-performance lithium metal battery electrolytes NATURE ENERGY 2022
- Capturing the swelling of solid-electrolyte interphase in lithium metal batteries. Science (New York, N.Y.) 1800; 375 (6576): 66-70
- Revealing and Elucidating ALD-Derived Control of Lithium Plating Microstructure ADVANCED ENERGY MATERIALS 2020
- Applications of atomic layer deposition and chemical vapor deposition for perovskite solar cells ENERGY & ENVIRONMENTAL SCIENCE 2020; 13 (7): 1997–2023