(Digital Presentation) Earth-Abundant Copper-Based Electrode Materials for Li-Ion Storage

Abstract

Lithium-ion batteries (LIBs) find their use in almost all applications starting from electronic gadgets to grid energy storage and hybrid electric vehicles. In this direction, the development of high-capacity anodes is crucial to fulfil the increasing energy demand. To evaluate the Li+ ion storage performance, we have synthesized an earth-abundant copper-based electrode material, Cu3PS4, using the chemical vapor transport (CVT) method from the constituent elements Cu, P, and S in a 3:1:4 ratio. It has an enargite-type structure and has a layered-type morphology (Figure 1a). A high capacity of 970 mAh g-1 is obtained at 0.1 A g-1 current density. The electrode is amenable for high discharge rates up to 5 A g-1, and at a discharge rate of 1 A g-1, the cell can be cycled 5000 times with 90% capacity retention. The high electrochemical performance of the material is related to the conversion reaction as probed by in situ Raman spectroscopy (Figure 1b) and surface-controlled capacitive contribution due to the formation of a polymeric film over the electrode surface. A full cell with LiCoO2 cathode results in a large number of cycles with stable performance. Further improvement is achieved by forming a composite with an organic polymer, polybenzimidazole. The composite electrode delivers almost double the capacity of the pristine electrode. Other studies on the use of the electrode material to multivalent ion storage based on Mg2+, Zn2+, and Al3+ are in progress.Reference D. Tripathy and S. Sampath, J. Power Sources 2020, 478, 229066. Figure 1. (a) Unit cell structure and SEM image of Cu3PS4 and (b) in situ Raman spectra of the electrode after discharge. Figure 1