Abstract
Mineral exploration forms a key approach for unveiling functional battery electrode materials. The synthetic preparation of naturally found minerals and their derivatives can aid in designing of new electrodes. Herein, saranchinaite Na2Cu(SO4)2 and its hydrated derivative kröhnkite Na2Cu(SO4)2·2H2O bisulfate minerals have been prepared using a facile spray drying route for the first time. The phase stability relation during the (de)hydration process was examined synergising in situ X-ray diffraction and thermochemical studies. Kröhnkite forms the thermodynamically stable phase as the hydration of saranchinaite to kröhnkite is highly exothermic (−51.51 ± 0.63 kJ mol−1). Structurally, kröhnkite offers a facile 2D pathway for Na+ ion migration resulting in 20 times higher total conductivity than saranchinaite at 60 °C. Both compounds exhibited a conversion redox mechanism for Li-ion storage with the first discharge capacity exceeding 650 mA h g−1 (at 2 mA g−1vs. Li+/Li) upon discharge up to 0.05 V. Post-mortem analysis revealed that the presence of metallic Cu in the discharged state is responsible for high irreversibility during galvanostatic cycling. This study reaffirms the exploration of Cu-based polyanionic sulfates, which while having limited (de)insertion properties, can be harnessed for conversion-based electrode materials for batteries.
| Original language | English |
|---|---|
| Pages (from-to) | 11169-11179 |
| Number of pages | 11 |
| Journal | Dalton Transactions |
| Volume | 51 |
| Issue number | 29 |
| DOIs | |
| State | Published - Jun 22 2022 |
Funding
The current work was financially supported by the Technology Mission Division (Department of Science and Technology, Govt. of India) under Materials for Energy Storage (MES-2018) program (DST/TMD/MES/2K18/207). SS thanks the Ministry of Human Resource Development (MHRD) for financial support. SS, AN, VP and PB thank the Indo-French Laboratory of Solid State Chemistry (LAFICS) for financial support. AN and KJ acknowledge the financial support from the U.S. Department of Energy, Office of Basic Energy Sciences, Grant DE-SC0021987. TD and SC are grateful to the HRI Allahabad and DST-SERB (SRG/2020/001707) for generous funding. Computational work was carried out at the cluster computing facility in the Harish-Chandra Research Institute. We acknowledge Prof. P. V. Kamath (Bangalore University) for providing in situ hydration XRD facility. PB is grateful to the Alexander von Humboldt Foundation (Bonn, Germany) for a Humboldt Fellowship for experienced researchers and Prof. Dr Maximilian Fichtner for hosting him at HIU, Ulm, Germany.