Lithium-Ion Battery Chemistries

A Primer

John T. Warner

• Publisher: Elsevier
• Year: 2019
• ISBN:
  9780128147795
• Topic: Scienze fisiche
• Subtopic: Chimica fisica e teoretica

Lithium-Ion Battery Chemistries: A Primer offers a simple description on how different lithium-ion battery chemistries work, along with their differences. It includes a refresher on the basics of electrochemistry and thermodynamics, and an understanding of the fundamental processes that occur in the lithium-ion battery. Furthermore, it reviews each of the major chemistries that are in use today, including Lithium-Iron Phosphate (LFP), Lithium-Cobalt Oxide (LCO), Lithium Manganese Oxide (LMO), Lithium-Nickel Manganese Cobalt (NMC), Lithium-Nickel Cobalt Aluminium (NCA), and Lithium-Titanate Oxide (LTO) and outlines the different types of anodes, including carbon (graphite, hard carbon, soft carbon, graphene), silicon, and tin.

In addition, the book offers performance comparisons of different chemistries to help users select the right battery for the right application and provides explanations on why different chemistries have different performances and capabilities. Finally, it offers a brief look at emerging and beyond-lithium chemistries, including lithium-air, zinc-air, aluminum air, solid-state, lithium-sulfur, lithium-glass, and lithium-metal.

• Presents a refresher on the basics of electrochemistry and thermodynamics, along with simple graphics and images of complex concepts
• Provides a clear-and-concise description of lithium-ion chemistries and how they operate
• Covers the fundamental processes that occur in lithium-ion batteries
• Includes a detailed review of current and future chemistries

Chapter 1

Introduction

Abstract

For many of us today electricity and lithium-ion batteries seem a lot like magic. Understanding just what magic is involved with bottling lightning and breaking down the “how” of lithium-ion batteries to give the reader a clear and simple understanding of what is happening inside the battery cell is the focus of this book. Chapter 1 introduces the purpose, which is to help demystify the topic of battery chemistries and how they work and offer clear and simple explanations using graphics and images. Subsequently, it describes the method that I used to develop this book and the processes I used to come to the knowledge within the book. Relying on the process of inquiry similar to how knowledge has been created for thousands of years by some of the greatest thinkers in human history such as Plato, DaVinci, and Einstein this book attempts to reduce the complexity of battery chemistry and its operation to make it simple and easy to understand.

Keywords

Lithium-ion; Battery; Rate of technology change; Battery eras; Industrial age; Portable age; Mobile age

Chapter Outline

• 1.1 Batteries and chemistry
• 1.2 Chapter outline

In Greek mythology Prometheus stole fire from Mount Olympus as a gift to humanity. That gift was to be the spark that enabled technology to allow human civilization to truly take off (Hesiod, 2008). Today, technology continues to be a boon helping to make human life easier. And in fact, it has really become the foundation for modern life. Technology is the undercurrent that makes modern life run, but as it has gotten more complex we find that we really don’t understand much about it or how it works—we just expect it to work. And lithium-ion batteries can be considered the core of much of modern technology—it is the source that powers our life. In fact, it’s not difficult to draw a similarity between Prometheus’ fire and the harnessing of electricity by Ben Franklin, Nikola Tesla, Thomas Edison, and others.

But much like the Greeks, few of us really have a good understanding of how these technologies work—lithium-ion batteries fall directly into that category. For the clear majority of people today batteries, much like automobiles, computers, smart phones, and other technologies, just work—until they don’t—we use them, we charge them, but we don’t really understand how they work. We do not entirely understand how they do what they do and usually do not care until they run out of juice. Arthur C. Clarke, futurist and science fiction author wrote “Any sufficiently advanced technology is indistinguishable from magic” (Clarke, 1977, p. 39) and in fact, for many of us today electricity and lithium-ion batteries do seem a lot like magic. Just what magic is involved with bottling lightning? That is the focus of this book and I will do my best to bring the technologies surrounding lithium-ion battery chemistries down to Earth much like Prometheus. This book will break down the “how” of lithium-ion batteries to give the reader a clear and simple understanding of what is happening inside the battery cell.

But the faster technology advances and the more mobile it becomes, the more dependent it is on having an adequate energy storage supply. Many current vehicle technologies, such as hybrid and electric vehicles, are enabled by the evolution of higher energy batteries that have allowed them to achieve greater fuel economy, electric drive capability, and reduced or even eliminating emissions. Even nonhybrid vehicles are highly dependent on electrical energy due to the emergence of technologies like lane departure warning, adaptive cruise controls, self-parking capabilities, and infotainment systems.

Other new technologies are emerging that are dependent on energy storage, such as autonomous vehicles, drones and unmanned aerial vehicles (UAVs), unmanned or autonomous underwater vehicles (UUVs and AUVs), unmanned delivery vehicles, and household robotics just to name a few. All these technologies are enabled through the advancement of energy storage technologies and lithium-ion batteries are the preferred solution for many of them.

And that only covers vehicle and transportation technologies! At the end of the 20th century Bill Gates himself forecast that technology was about to bring humankind to an inflection point where “…change in consumer use becomes sudden and massive” (Gates & Hemingway, 1999, p. xvi) that will create radical change in both our business and personal lives. Of course, Gates was referring to the impact of the internet, digital information, and connectivity which has not only proven to be a very accurate statement but may actually have underestimated the impact. Throughout the rest of our daily lives the addition and embedding of technologies such as the Internet of Things (IoT) (International Telecommunication Union (ITU), 2017) which describes all technologies that are interconnected through a network of communications and are today embedded in every aspect of our life. This includes smart phones, tablet computers, laptop computers, desktop computers, fitbits, 3D printers, smart thermostats, smart refrigerators, smart televisions, and an ever-increasing number of other appliances and tools. These technologies have a couple of things in common. One is that they are all becoming wireless and they can virtually all be connected via a wireless network and second is that many of them need some form of energy storage system, in other words a battery, to provide their power.

New medical technologies are being introduced every day due to the increasing capabilities of energy storage technologies. From wireless technology used in hospital equipment to implantable devices to wireless tools that can be used to diagnose and treat patients in remote villages that have no electrical infrastructure. All of these technologies are enabled due to the regular improvements that batteries have experienced over the past few years. And as the use of medical nanobots and microbots increases the next generation of solid-state batteries are being used to power them.

Wearable technology is also beginning to emerge in many different types of products, and electronics are even beginning to get embedded in our clothing. Beginning with the evolution of the wristwatch into a device that monitors your health, the number of steps you take, the number of steps you climb and now you can even get your email and your text messages on your wrist. Companies like Google have introduced technologies like their Google Glasses, to allow users to access the internet using eye tracking technologies. This is evolving into a new realm of virtual reality devices that allow us to see the world around us in a different manner. All these factors have pushed the demands on batteries even further.

As we have watched technology around us continue to evolve into more complex systems, it seems that our understanding of how things work has diminished at an equal rate, kind of like an inverse Moore’s Law. Think about that for a moment, do you really know how your smart phone works? What about your laptop or tablet computer, do you know what the different components are within them, what the software is made up of and how they function? Even your automobile has become a moving computer, 30 years ago it was common place for most people to be able to service their own vehicles but today you just about need to be an electrical engineer to work on a car. There’s not much room for the backyard mechanics any longer.

The speed of technology change continues to grow at an increasing rate. Looking at the length of the curves in Fig. 1 (Felton, 2008), we see that newer technologies appear to be seeing higher levels of adoption at a much faster rate than older technologies. For example, while the internet took only 15 years to reach 60% of U.S. households, the automobile took more than 50 years to reach and sustain 60% market penetration. Gordon Moore, cofounder of Intel, coined what came to become described as “Moore’s Law” to describe the rate of technology change in relation to computer processors. Moore’s prediction that the number of components on a chip would double every year ended up being pretty accurate.

Fig. 1 Rate of technology change.

However, batteries have not experienced the same rate of change as computer processors. For nearly 150 years lead acid batteries were the pillar of battery technology, with very little change in energy density but significant improvements in manufacturability, life, and cost. Even modern nickel metal hydride batteries were not introduced until the early 1980s and not commercialized in large numbers until the early 1990s. The first commercial lithium-ion batteries were not introduced until 1991 but had been in development for more than a decade prior to their commercial introduction. In less than 30 years since their introduction lithium-ion batteries have grown from use in luxury devices to becoming the platform that powers our daily lives. In fact, if we look at the introduction of different secondary (rechargeable) batteries over the past 130 years we see three distinct stages of battery development. But the introduction of these newer chemistries did not displace the traditional lead acid batteries, in almost every case they ended up in a complementary or new product that could not have been served adequately by lead acid. Lead acid batteries continue to be the mainstay for vehicle starting and many other applications, and while we have seen some premium vehicles moving toward 12-V lithium-ion these prove to be the exception and not the rule but today battery technology is changing quickly.

As shown in Fig. 2 when we look at secondary battery energy density over time there appear to be three stages of battery development that have occurred over the past 130 years. The first stage I will call the “Industrial Age” of batteries as these were the earliest batteries used to help power the burgeoning global Industrial Revolution era technologies. These batteries included many variations of lead acid batteries, Thomas Edison’s nickel-zinc and nickel-iron batteries, the sealed nickel-cadmium battery, the valve-regulated lead acid battery, and ended with the introduction of the first nickel metal hydride batteries. During this Industrial Age of batteries the manufacturing processes were improved, the costs were reduced, and the cycle life was increased, but there was not much improvement in energy density of secondary batteries during this period. During this nearly 100-year period we saw specific energy density increase on an average of only about 0.2 Wh/kg per year.

Fig. 2 Modern battery-specific energy over time.

The next stage of battery development I will call the “Portable Age” as it coincided with the introduction of so many mobile technologies like the laptop computer, cell phone, smart phone, tablet computer, music player, video game, and many other technologies. During this period humanity began demanding that we should be able to bring our technologies with us everywhere we went, which led to the massive growth in mobile energy needs for these technologies. It was during this period that cellular telephones became commonplace and began to replace the land lines that had dominated personal communication for over a century. During this period we also saw the introduction of the laptop computer. Lithium-ion battery technology enabled both of these tools and gave them the power they needed to become everyday household items by making them truly portable. This Portable Age of batteries roughly begins with the introduction of the first commercial lithium-ion battery in 1991 at just under 90 Wh/kg and continues to late 2008/2009 when cell energy densities reached about 180 Wh/kg effectively doubling the energy in a battery cell.

Today, there is yet another energy storage shift happening as we move from simply portable to truly mobile. In this third age of batteries, the “Mobile Age,” we see the battery technologies finally achieving high enough energies to be able to fully electrify vehicles. These efforts began in earnest in the mid-2000s but it was the 2009 introduction by the U.S. government of the American Reinvestment and Recovery Act (ARRA) which provided more than $2.3 billion dollars for “…renewable energy generation, energy storage, advanced transmission, energy conservation, renewable fuel refining or blending, plug-in vehicles, and carbon capture and storage” (The White House: Office of the Press Secretary, 2016). This investment in the U.S. battery manufacturing industry led to the emergence of several companies that still continue to be major players in the world market today, these investments included an EnerDel factory in Indiana, and Dow-Kokam, Johnson Controls, A123 and LG Chem factories in Michigan, a Saft plant in Florida, as well as many other investments in battery manufacturing, recycling, and clean energy. These investments helped to accelerate the development of lithium-ion batteries and led to the current technologies that have reached as much as 285 Wh/kg. This equates to a specific energy density increase of an average of 10.5 Wh/kg per year over the past 28 years during the Portable and Mobile ages of batteries. So, comparing the Mobile and Portable Age rates of improvement to the Industrial Age rate of improvement, and then to the previous era of specific energy density the improvement is more than 51.5 times faster and even within the Mobile Age specific energy densities have increased in the range of 200% since the beginning of the Portable Age.

Of course, looking at it from the energy density perspective is o...