A Hybrid Mineral Battery: Energy Storage and Dissolution Behavior of CuFeS₂ in a Fixed Bed Flow Cell

Abstract

The development of a hybrid system capable of storing energy and the additional benefit of Cu extraction is discussed in this work. A fixed bed flow cell (FBFC) was used in which a composite negative electrode containing CuFeS (80 wt %) and carbon black (20 wt %) in graphite felt was separated from a positive (graphite felt) electrode by a proton-exchange membrane. The anolyte (0.2 m H SO ) and catholyte (0.5 m Fe in 0.2 m H SO with or without 0.1 m Cu ) were circulated in the cell. The electrochemical activity of the Fe /Fe redox couple over graphite felt significantly improved after the addition of Cu in the catholyte. Ultimately, in the CuFeS ∥Fe /Cu (CFeCu) FBFC system, the specific capacity increased continuously to 26.4 mAh g in 500 galvanostatic charge-discharge (GCD) cycles, compared to the CuFeS ∥Fe (CFe) system (13.9 mAh g ). Interestingly, the specific discharge energy gradually increased to 3.6 Wh kg in 500 GCD cycles for the CFeCu system compared to 3.29 Wh kg for the CFe system in 150 cycles. In addition to energy storage, 10.75 % Cu was also extracted from the mineral, which is an important feature of the CFeCu system as it would allow Cu extraction and recovery through hydrometallurgical methods.

Thermoelectric Driven Self-Powered Water Electrolyzer Using Nanostructured CuFeS2 Plates as Bifunctional Electrocatalyst

“… The X-ray diffraction pattern (Figure A) indicated the observation of major diffraction peaks at 29.42, 48.74, 49.12, 57.88, and 58.56° could be indexed to the (112), (220), (204), (312), and (116) planes and the minor peaks at 33.94, 34.44, 71.34, 78.92, and 79.76° can be indexed to (200), (004), (400), (332), and (316) lattice planes of tetragonal CuFeS 2 with a space group of I 4̅2 d symmetry. The obtained XRD pattern is well-matched with the JCPDS card number: 37–0471 . It is worth noting that there are no peaks related to CuS, FeS 2 , and any oxide/hydroxides observed in the X-ray diffraction pattern, which suggested that the prepared CuFeS 2 is of high purity.…”

“…The obtained XRD pattern is well-matched with the JCPDS card number: 37−0471. 45 It is worth noting that there are no peaks related to CuS, FeS 2 , and any oxide/ hydroxides observed in the X-ray diffraction pattern, which suggested that the prepared CuFeS 2 is of high purity. Figures S2 and S3 show the XRD patterns of the prepared CuS (hexagonal, JCPDS 01-078-0876) and FeS 2 (orthorhombic, Figure 1E shows the deconvoluted spectra of Fe 2p, reflecting the presence of two peaks at 712.5 and 725.3 eV, which is fitted to the Fe 3+ 2p 3/2 and Fe 3+ 2p 1/2 .…”

The Mineral Battery: Combining Metal Extraction and Energy Storage

“…The reversible transformation of sulfide sulfur species (S 2 2-/ S 2-) formed on the surface of sulfidic mineral particles and reversible faradaic processes (adsorption and/or desorption of ionic species) on AC may facilitate the energy storage during repetitive charge and discharge cycles, as reported elsewhere. 11 The use of renewable energy sources and the installation of a TFB at remote mine sites could significantly reduce GHG emissions by limiting the consumption of fossil fuels. While irreversible faradaic processes, such as Cu dissolution and other reactions involving impurities, occur during the charging cycle, these also result in desirable Cu extraction of about 16.1% in 100 cycles or about 12.2 h. 10 A specific example of how a TFB could be applied at a British Columbia mine is now given.…”

Redox Targeting of Energy Materials for Energy Storage and Conversion

“…Apart from the aforementioned energy storage and conversion applications, the RT process, for which the solid functional material and electrode stay spatially separated while electrically wired via a regenerative electrochemical–chemical cycle of redox mediator, has versatile intriguing applications in other fields, such as hydrometallurgical mineral extraction, [ 63 ] electrochromic windows, [ 64 ] and spent battery materials recycling. [ 65 ] Currently, the industrially implemented recycling technologies of spent Li‐ion batteries are primarily pyrometallurgy and hydrometallurgy.…”