Using defects to store energy in materials – a computational study

Abstract

Energy storage occurs in a variety of physical and chemical processes. In particular, defects in materials can be regarded as energy storage units since they are long-lived and require energy to be formed. Here, we investigate energy storage in non-equilibrium populations of materials defects, such as those generated by bombardment or irradiation. We first estimate upper limits and trends for energy storage using defects. First-principles calculations are then employed to compute the stored energy in the most promising elemental materials, including tungsten, silicon, graphite, diamond and graphene, for point defects such as vacancies, interstitials and Frenkel pairs. We find that defect concentrations achievable experimentally (~0.1–1 at.%) can store large energies per volume and weight, up to ~5 MJ/L and 1.5 MJ/kg for covalent materials. Engineering challenges and proof-of-concept devices for storing and releasing energy with defects are discussed. Our work demonstrates the potential of storing energy using defects in materials.

Revealing the Nature of Defects in α-Ag2WO4 by Positron Annihilation Lifetime Spectroscopy: A Joint Experimental and Theoretical Study

“…For scientists, the management of the presence of defects, which can be associated with a structural and electronic disorder, may enable the creation of new materials with unique, impossible physical properties for well-ordered crystal structures [8][9][10][11] . To understand the nature of the defects and their formation and removal mechanisms in semiconductors constitutes a very challenging topic in materials science [11][12][13] .…”

“…In the field of solid materials, the ideal crystal formed by the periodic replication of unit cells does not exist. In reality, crystals are exposed to lattice vibrations, contain defects, and have surface and bulk vacancies, impurities, and nonstoichiometric compositions. − For scientists, the management of the presence of defects, which can be associated with a structural and electronic disorder, may enable the creation of new materials with unique, impossible physical properties for well-ordered crystal structures. − Understanding the nature of the defects and their formation and removal mechanisms in semiconductors constitutes a very challenging topic in materials science. − …”

A Novel Interstitial Site in Binary Rock-Salt Compounds

“…In our previous study, we investigated two Frenkel defects due to base- and body-interstitial occupancies in PbS [ 36 ]. In addition, point defects are used to store energy in materials [ 3 ], and these Frenkel defects must be considered in the study.…”

“…Point defects in materials lead to structural, electrical, and mechanical changes, which can be detrimental in some applications [ 1 ], e.g., point defects can affect energy storage capacity [ 2 , 3 ], catalyze chemical reactions [ 2 ], control light emission efficiency [ 4 , 5 ], and tune the thermal [ 6 , 7 , 8 ] and electrical [ 9 , 10 ] properties of materials. Point defects have finite formation energies and are established as equilibrium species in a crystal.…”

Chemistry–mechanics–geometry coupling in positive electrode materials: a scale-bridging perspective for mitigating degradation in lithium-ion batteries through materials design

“…75 From a thermodynamics perspective, it is crucial to consider that point defects store energy in crystalline materials (proportional to the defect formation energy) and, thus, represent high-energy states in the lattice. 76 In multiphasic intercalation systems, these high-energy states have been shown to act as nucleation points for phase transformations. 29 By leveraging this relationship, one can envision an approach where defects are engineered before cycling to synergistically alter the nucleation and growth process to minimize stress and unwanted plasticity.…”