The rapid growth, demand, and production of batteries to meet various emerging applications, such as electric vehicles and energy storage systems, will result in waste and disposal problems in the next few years as these batteries reach end-of-life. Battery reuse and recycling are becoming urgent worldwide priorities to protect the environment and address the increasing need for critical metals. As a review article, this paper reveals the current global battery market and global battery waste status from which the main battery chemistry types and their management, including reuse and recycling status, are discussed. This review then presents details of the challenges, opportunities, and arguments on battery second-life and recycling. The recent research and industrial activities in the battery reuse domain are summarized to provide a landscape picture and valuable insight into battery reuse and recycling for industries, scientific research, and waste management.

Electrochemical cells and systems play a key role in a wide range of industry sectors. These devices are critical enabling technologies for renewable energy; energy management, conservation and storage; pollution control / monitoring; and greenhouse gas reduction. A large number of electrochemical energy technologies have been developed in the past. These systems continue to be optimized in terms of cost, life time and performance, leading to their continued expansion into existing and emerging market sectors. The more established technologies such as deep-cycle batteries and sensors are being joined by emerging technologies such as fuel cells, large format lithium-ion batteries, electrochemical reactors; ion transport membranes and supercapacitors. This growing demand (multi billion dollars) for electrochemical energy systems along with the increasing maturity of a number of technologies is having a significant effect on the global research and development effort which is increasing in both in size and depth. A number of new technologies, which will have substantial impact on the environment and the way we produce and utilize energy, are under development. This paper presents an overview of several emerging electrochemical energy technologies along with a discussion some of the key technical challenges.

At first glance, the combination of the lightest, most electropositive metal (lithium) with a safe, abundant (and reasonably light) non-metal (sulfur) makes good sense as a prospective battery. However, while the lithium–sulfur battery offers a very high theoretical specific energy (∼2600 W h kg⁻¹) the actual performance delivered is proving to be severely limited—in many cases, this is directly related to the role of the electrolyte. The fundamental issue is that the reduction of sulfur proceeds through a series of polysulfide species, which are for the most part soluble in common organic solvents, including those employed in battery electrolyte solutions. So, despite the fact that the ultimate product (Li₂S) is essentially insoluble, the intermediate stages of discharge see a migration of redox-active species out of the cathode, from where they can react with the lithium anode, which sets in train a series of equilibria that cause both a loss of charging efficiency and a gradual loss of discharge capacity. In the last decade, a major stream of the research to overcome this complex situation has focused on minimizing the solubility of polysulfides. From this we now have a range of media in which the lithium–sulfur system can operate with much improved charge–discharge characteristics: ionic liquids (and blends with organic media); super-saturated salt-solvent mixtures; polymer-gelled organic media; solid polymers; solid inorganic glasses. Underlining the multi-faceted nature of interactions within the lithium–sulfur cell, though, none of these improved electrolytes has been able to bring the performance of this system up to the levels of reliability and capacity maintenance (without sacrificing high specific energy) that are benchmarks in energy storage applications. Our survey indicates that only by combining particular electrolytes with cathode materials that are designed to actively retain sulfur and its reduction products, have a relatively few studies been able to obtain the desired levels of performance. Ultimately the successful development of the lithium–sulfur battery requires careful coordination of the choice of modified electrolyte with the specific nature of the cathode material, underpinned by the assumption that the resulting electrolyte composition will meet established criteria for compatibility with the lithium anode.

Lithium-sulfur batteries can displace lithium-ion by delivering higher specific energy. Presently, however, the superior energy performance fades rapidly when the sulfur electrode is loaded to the required levels—5 to 10 mg cm⁻²— due to substantial volume change of lithiation/delithiation and the resultant stresses. Inspired by the classical approaches in particle agglomeration theories, we found an approach that places minimum amounts of a high-modulus binder between neighboring particles, leaving increased space for material expansion and ion diffusion. These expansion-tolerant electrodes with loadings up to 15 mg cm⁻² yield high gravimetric (>1200 mA·hour g⁻¹) and areal (19 mA·hour cm⁻²) capacities. The cells are stable for more than 200 cycles, unprecedented in such thick cathodes, with Coulombic efficiency above 99%.