Wangda Li

Bio: Wangda Li is an academic researcher from University of Texas at Austin. The author has contributed to research in topics: Lithium & Cathode. The author has an hindex of 23, co-authored 28 publications receiving 2881 citations.

High-voltage positive electrode materials for lithium-ion batteries

Abstract: The ever-growing demand for advanced rechargeable lithium-ion batteries in portable electronics and electric vehicles has spurred intensive research efforts over the past decade. The key to sustaining the progress in Li-ion batteries lies in the quest for safe, low-cost positive electrode (cathode) materials with desirable energy and power capabilities. One approach to boost the energy and power densities of batteries is to increase the output voltage while maintaining a high capacity, fast charge–discharge rate, and long service life. This review gives an account of the various emerging high-voltage positive electrode materials that have the potential to satisfy these requirements either in the short or long term, including nickel-rich layered oxides, lithium-rich layered oxides, high-voltage spinel oxides, and high-voltage polyanionic compounds. The key barriers and the corresponding strategies for the practical viability of these cathode materials are discussed along with the optimization of electrolytes and other cell components, with a particular emphasis on recent advances in the literature. A concise perspective with respect to plausible strategies for future developments in the field is also provided.

High-nickel layered oxide cathodes for lithium-based automotive batteries

Abstract: High-nickel layered oxide cathode materials will be at the forefront to enable longer driving-range electric vehicles at more affordable costs with lithium-based batteries. A continued push to higher energy content and less usage of costly raw materials, such as cobalt, while preserving acceptable power, lifetime and safety metrics, calls for a suite of strategic compositional, morphological and microstructural designs and efficient material production processes. In this Perspective, we discuss several important design considerations for high-nickel layered oxide cathodes that will be implemented in the automotive market for the coming decade. We outline various intrinsic restraints of maximizing their energy output and compare current/emerging development roadmaps approaching low-/zero-cobalt chemistry. Materials production is another focus, relevant to driving down costs and addressing the practical challenges of high-nickel layered oxides for demanding vehicle applications. We further assess a series of stabilization techniques on their prospects to fulfill the aggressive targets of vehicle electrification. The development of high-nickel layered oxide cathodes represents an opportunity to realize the full potential of lithium-ion batteries for electric vehicles. Manthiram and colleagues review the materials design strategies and discuss the challenges and solutions for low-cobalt, high-energy-density cathodes.

Dynamic behaviour of interphases and its implication on high-energy-density cathode materials in lithium-ion batteries.

Abstract: Undesired electrode-electrolyte interactions prevent the use of many high-energy-density cathode materials in practical lithium-ion batteries. Efforts to address their limited service life have predominantly focused on the active electrode materials and electrolytes. Here an advanced three-dimensional chemical and imaging analysis on a model material, the nickel-rich layered lithium transition-metal oxide, reveals the dynamic behaviour of cathode interphases driven by conductive carbon additives (carbon black) in a common nonaqueous electrolyte. Region-of-interest sensitive secondary-ion mass spectrometry shows that a cathode-electrolyte interphase, initially formed on carbon black with no electrochemical bias applied, readily passivates the cathode particles through mutual exchange of surface species. By tuning the interphase thickness, we demonstrate its robustness in suppressing the deterioration of the electrode/electrolyte interface during high-voltage cell operation. Our results provide insights on the formation and evolution of cathode interphases, facilitating development of in situ surface protection on high-energy-density cathode materials in lithium-based batteries.

Mn versus Al in Layered Oxide Cathodes in Lithium-Ion Batteries: A Comprehensive Evaluation on Long-Term Cyclability

Abstract: DOI: 10.1002/aenm.201703154 (LiNi1−xMxO2, M = Co, Mn, and Al), has witnessed widespread commercialization with compositions such as LiNi1/3Co1/3Mn1/3O2 and LiNi0.8Co0.15Al0.05O2 (NCA).[4–6] To further boost the energy density of state-of-the-art Li-ion batteries to above 300 W h kg−1, a higher nickel incorporation in LiNi1−x−yCoxMnyO2 cathodes (NCM; 1−x−y ≥0.6)[7–10] and/or an extension of their voltage window (≥4.5 V vs Li+/Li)[11–14] are pursued. In addition, compared to NCA, Ni-rich NCM materials, such as LiNi0.8Co0.1Mn0.1O2, offer thermal stability and cost advantages as well as ease for microstructural/compositional fine tuning.[5,9] However, the above approaches significantly degrade the cycle and calendar life of the battery. Thus, a firm understanding of the underlying mechanisms responsible is required for practical deployment of the Ni-rich NCM cathodes in EVs and other fields. It has been recognized thus far that the cell performance deterioration, in terms of both capacity and working voltage, originates from aggressive chemical, structural, and mechanical degradation occurring on both Ni-based layered oxide cathodes and graphite anodes.[1,6,15,16] These pernicious reactions include (i) parasitic oxidation of electrolyte components catalyzed by the delithiated Li1−yNi1−xM xO2 at high voltages,[7,12,17] (ii) dissolution of the active cathode material aggravated by acidic species attack from the electrolyte (e.g., HF),[17–21] (iii) irreversible structural rearrangement (especially at the surface) that forms a Li-deficient, highly resistive rocks-salt phase (NiO),[22–26] (iv) microcrack generation and the eventual pulverization of bulk cathode particles, induced by large internal strains during repeated delithiation/lithiation,[27–31] Nickel-rich layered oxide cathodes with the composition LiNi1−x−yCoxMnyO2 (NCM, (1−x−y) ≥ 0.6) are under intense scrutiny recently to contend with commercial LiNi0.8Co0.15Al0.05O2 (NCA) for high-energy-density batteries for electric vehicles. However, a comprehensive assessment of their electrochemical durability is currently lacking. Herein, two in-house cathodes, LiNi0.8Co0.15Al0.05O2 and LiNi0.7Co0.15Mn0.15O2, are investigated in a highvoltage graphite full cell over 1500 charge-discharge cycles (≈5–10 year service life in vehicles). Despite a lower nickel content, NCM shows more performance deterioration than NCA. Critical underlying degradation processes, including chemical, structural, and mechanical aspects, are analyzed via an arsenal of characterization techniques. Overall, Mn substitution appears far less effective than Al in suppressing active mass dissolution and irreversible phase transitions of the layered oxide cathodes. The active mass dissolution (and crossover) accelerates capacity decline with sustained parasitic reactions on the graphite anode, while the phase transitions are primarily responsible for cell resistance increase and voltage fade. With Al doping, on the other hand, secondary particle pulverization is the more limiting factor for long-term cyclability compared to Mn. These results establish a fundamental guideline for designing high-performing Ni-rich NCM cathodes as a compelling alternative to NCA and other compositions for electric vehicle applications.

Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review.

Abstract: The lithium metal battery is strongly considered to be one of the most promising candidates for high-energy-density energy storage devices in our modern and technology-based society. However, uncontrollable lithium dendrite growth induces poor cycling efficiency and severe safety concerns, dragging lithium metal batteries out of practical applications. This review presents a comprehensive overview of the lithium metal anode and its dendritic lithium growth. First, the working principles and technical challenges of a lithium metal anode are underscored. Specific attention is paid to the mechanistic understandings and quantitative models for solid electrolyte interphase (SEI) formation, lithium dendrite nucleation, and growth. On the basis of previous theoretical understanding and analysis, recently proposed strategies to suppress dendrite growth of lithium metal anode and some other metal anodes are reviewed. A section dedicated to the potential of full-cell lithium metal batteries for practical applicatio...

30 Years of Lithium-Ion Batteries.

Abstract: Over the past 30 years, significant commercial and academic progress has been made on Li-based battery technologies. From the early Li-metal anode iterations to the current commercial Li-ion batteries (LIBs), the story of the Li-based battery is full of breakthroughs and back tracing steps. This review will discuss the main roles of material science in the development of LIBs. As LIB research progresses and the materials of interest change, different emphases on the different subdisciplines of material science are placed. Early works on LIBs focus more on solid state physics whereas near the end of the 20th century, researchers began to focus more on the morphological aspects (surface coating, porosity, size, and shape) of electrode materials. While it is easy to point out which specific cathode and anode materials are currently good candidates for the next-generation of batteries, it is difficult to explain exactly why those are chosen. In this review, for the reader a complete developmental story of LIB should be clearly drawn, along with an explanation of the reasons responsible for the various technological shifts. The review will end with a statement of caution for the current modern battery research along with a brief discussion on beyond lithium-ion battery chemistries.

Pathways for practical high-energy long-cycling lithium metal batteries

Abstract: State-of-the-art lithium (Li)-ion batteries are approaching their specific energy limits yet are challenged by the ever-increasing demand of today’s energy storage and power applications, especially for electric vehicles. Li metal is considered an ultimate anode material for future high-energy rechargeable batteries when combined with existing or emerging high-capacity cathode materials. However, much current research focuses on the battery materials level, and there have been very few accounts of cell design principles. Here we discuss crucial conditions needed to achieve a specific energy higher than 350 Wh kg−1, up to 500 Wh kg−1, for rechargeable Li metal batteries using high-nickel-content lithium nickel manganese cobalt oxides as cathode materials. We also provide an analysis of key factors such as cathode loading, electrolyte amount and Li foil thickness that impact the cell-level cycle life. Furthermore, we identify several important strategies to reduce electrolyte-Li reaction, protect Li surfaces and stabilize anode architectures for long-cycling high-specific-energy cells. Jun Liu and Battery500 Consortium colleagues contemplate the way forward towards high-energy and long-cycling practical batteries.

A reflection on lithium-ion battery cathode chemistry

Abstract: Lithium-ion batteries have aided the portable electronics revolution for nearly three decades. They are now enabling vehicle electrification and beginning to enter the utility industry. The emergence and dominance of lithium-ion batteries are due to their higher energy density compared to other rechargeable battery systems, enabled by the design and development of high-energy density electrode materials. Basic science research, involving solid-state chemistry and physics, has been at the center of this endeavor, particularly during the 1970s and 1980s. With the award of the 2019 Nobel Prize in Chemistry to the development of lithium-ion batteries, it is enlightening to look back at the evolution of the cathode chemistry that made the modern lithium-ion technology feasible. This review article provides a reflection on how fundamental studies have facilitated the discovery, optimization, and rational design of three major categories of oxide cathodes for lithium-ion batteries, and a personal perspective on the future of this important area. The 2019 Nobel Prize in Chemistry has been awarded to a trio of pioneers of the modern lithium-ion battery. Here, Professor Arumugam Manthiram looks back at the evolution of cathode chemistry, discussing the three major categories of oxide cathode materials with an emphasis on the fundamental solid-state chemistry that has enabled these advances.

Guidelines and trends for next-generation rechargeable lithium and lithium-ion batteries.

Abstract: Commercial lithium-ion (Li-ion) batteries suffer from low energy density and do not meet the growing demands of the energy storage market. Therefore, building next-generation rechargeable Li and Li-ion batteries with higher energy densities, better safety characteristics, lower cost and longer cycle life is of outmost importance. To achieve smaller and lighter next-generation rechargeable Li and Li-ion batteries that can outperform commercial Li-ion batteries, several new energy storage chemistries are being extensively studied. In this review, we summarize the current trends and provide guidelines towards achieving this goal, by addressing batteries using high-voltage cathodes, metal fluoride electrodes, chalcogen electrodes, Li metal anodes, high-capacity anodes as well as useful electrolyte solutions. We discuss the choice of active materials, practically achievable energy densities and challenges faced by the respective battery systems. Furthermore, strategies to overcome remaining challenges for achieving energy characteristics are addressed in the hope of providing a useful and balanced assessment of current status and perspectives of rechargeable Li and Li-ion batteries.