Lithium metal is light (with a density of 0.534 g/cm3), has a specific capacity of 3860 mAh per gram, and has the highest electroactivity with redox potential of –3.04 against the standard hydrogen electrode. It should be the ideal anode material for rechargeable batteries. So what is stopping it? This book analyzes two barriers to the commercial development of rechargeable batteries with lithium-metal anodes: growth of lithium dendrites and low Coulombic efficiency of lithium cycling in the battery. At one time, the problems were considered insurmountable, and interest shifted to compromise candidates: disordered carbon and then to the present-day ordered graphite anode.
Is there a second coming for lithium-metal anodes? This book provides a structured response to this question. A brief introductory chapter on rechargeable batteries sets the stage for the use of lithium-metal anodes. The chapter introduces tree-like structures—with the generic name of dendrites—growing on the anode during charge/discharge cycles. These form internal short circuits, causing capacity loss. Chapter 2 describes seven techniques used to characterize the surface morphology and chemistry of dendrites. Micrographs and schematics contribute to the lucid description of test methods and failure mechanisms of the lithium anode. The chapter also discusses the important role of the solid-electrolyte interface. Theoretical models, including recent ones emphasizing interfacial elastic strength, are described. Chapter 3 discusses factors affecting Coulombic efficiency and dendrite growth, since most of them are common to both. The chapter also discusses various electrolytes and the influence of solvents, lithium salts, additives, and electrolyte concentration.
Chapter 4 considers the application of lithium-metal anodes mainly in lithium-sulfur and lithium-air batteries. The chapter also covers rechargeable batteries where a lithium-metal anode is formed in situ. Application of nanotechnology and progress in modeling and experimental work have led to new electrolytes and additives being used in batteries with lithium-metal anodes. Chapter 5 reviews these advances and offers perspectives on the future development of lithium-metal anodes.
References are extensive and cover the work completed up until 2015, with a few references from 2016. This is a valuable reference for people working in rechargeable batteries in general and lithium-metal anodes in particular. It is timely because the lithium anode has remained the holy grail for four decades, and recent developments discussed in the book may well take us nearer to the goal.
Reviewer: N. Balasubramanian is an independent research scholar working in Bangalore, India.
