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.

https://www.nature.com/articles/s41560-019-0513-0.pdf?proof=t

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

The goal of limiting global warming to 1.5 °C requires a drastic reduction in CO2 emissions across many sectors of the world economy. Batteries are vital to this endeavor, whether used in electric vehicles, to store renewable electricity, or in aviation. Present lithium-ion technologies are preparing the public for this inevitable change, but their maximum theoretical specific capacity presents a limitation. Their high cost is another concern for commercial viability. Metal-air batteries have the highest theoretical energy density of all possible secondary battery technologies and could yield step changes in energy storage, if their practical difficulties could be overcome. The scope of this review is to provide an objective, comprehensive, and authoritative assessment of the intensive work invested in nonaqueous rechargeable metal-air batteries over the past few years, which identified the key problems and guides directions to solve them. We focus primarily on the challenges and outlook for Li-O2 cells but include Na-O2, K-O2, and Mg-O2 cells for comparison. Our review highlights the interdisciplinary nature of this field that involves a combination of materials chemistry, electrochemistry, computation, microscopy, spectroscopy, and surface science. The mechanisms of O2 reduction and evolution are considered in the light of recent findings, along with developments in positive and negative electrodes, electrolytes, electrocatalysis on surfaces and in solution, and the degradative effect of singlet oxygen, which is typically formed in Li-O2 cells.

/pdf/lithium-oxygen-batteries-and-related-systems-potential-1kvfepaqwx.pdf

Lithium-Oxygen Batteries and Related Systems: Potential, Status, and Future

This Review provides a comprehensive overview of LiNiO2 (LNO), almost 30 years after its introduction as a cathode active material. We aim to highlight the physicochemical peculiarities that make LNO a complex material in every aspect. We specifically stress the effect of the Li off-stoichiometry (Li1-z Ni1+z O2 ) on every property of LNO, especially the electrochemical ones. The key instability issues that plague the compound and the strategies that have been implemented so far to overcome them are discussed in detail. Finally, the open questions that remain to be addressed by the scientific community are summarized, and the research directions that seem the most promising to enable LNO to be fully exploited are elucidated.

There and Back Again-The Journey of LiNiO2 as a Cathode Active Material.

Lithium-ion batteries - current state of the art and anticipated developments

Ni-rich materials of layered structure LiNixCoyMnzO2, x > 0.5, are promising candidates as cathodes in high-energy-density Li-ion batteries for electric vehicles. The structural and cycling stability of Ni-rich cathodes can be remarkably improved by doping with a small amount of extrinsic multivalent cations. In this study, we examine development of a fast screening methodology for doping LiNi0.8Co0.1Mn0.1O2 with cations Mg2+, Al3+, Si4+, Ti4+, Zr4+, and Ta5+ by a “top-down” approach. The cathode material is coated by a precursor layer that contains the dopant, which then is introduced into the particles by diffusion during heat treatment at elevated temperatures. The methodology described herein can be applied to Ni-rich cathode materials and allows relatively easy and prompt identification of the most promising dopants. Then further optimization work can lead to development of high-capacity stable cathode materials. The present study marks Ta5+ cations as very promising dopants for Ni-rich NCM cathodes.

Structural and Electrochemical Aspects of LiNi0.8Co0.1Mn0.1O2 Cathode Materials Doped by Various Cations

Development of advanced high energy density lithium ion batteries is important for promoting electromobility. Making electric vehicles attractive and competitive compared to conventional automobiles depends on the availability of reliable, safe, high power, and highly energetic batteries whose components are abundant and cost effective. Nickel rich Li[NixCoyMn1−x−y]O2 layered cathode materials (x > 0.5) are of interest because they can provide very high specific capacity without pushing charging potentials to levels that oxidize the electrolyte solutions. However, these cathode materials suffer from stability problems. We discovered that doping these materials with tungsten (1 mol%) remarkably increases their stability due to a partial layered to cubic (rock salt) phase transition. We demonstrate herein highly stable Li ion battery prototypes consisting of tungsten-stabilized Ni rich cathode materials (x > 0.9) with specific capacities >220 mA h g-1. This development can increase the energy density of Li ion batteries more than 30% above the state of the art without compromising durability.

Q. Zhang

Papers

Pushing the limit of layered transition metal oxide cathodes for high-energy density rechargeable Li ion batteries