Editing Covellite (section)

==Applications==

=== Superconductors ===
Covellite was the first identified naturally occurring [[superconductor]].<ref name="Ben2006">{{cite journal|author1=Benedetto, F.D.|author2=Borgheresi, M.|author3=Caneschi, A.|author4=Chastanet, G.|author5=Cipriani, C.|author6=Gatteschi, D.|author7=Pratesi, G.|author8=Romanelli, M.|author9=Sessoli, R.|year=2006|title=First evidence of natural superconductivity|journal=[[European Journal of Mineralogy]]|volume=18|issue=3|pages=283–287|bibcode=2006EJMin..18..283D|doi=10.1127/0935-1221/2006/0018-0283}}</ref> The framework of CuS<sub>3</sub> /CuS<sub>2</sub> allow for an electron excess that facilitate superconduction during particular states, with exceptionally low thermal loss. Material science is now aware of several of covellite's favorable properties and several researchers are intent on synthesizing covellite.<ref>{{cite journal|author1=Chunyan Wu|author2=Shu-Hong Yu|author3=Markus Antoniette|year=2006|title=Complex Concaved Cuboctahedrons of Copper Sulfide Crystals with Highly Geometrical Symmetry Created by a Solution Process|journal=[[Chemistry of Materials]]|volume=18|issue=16|pages=3599–3601|doi=10.1021/cm060956u}}</ref><ref>{{cite journal|last1=Nava|first1=Dora|last2=Gonzalez|first2=I|display-authors=etal|year=2006|title=Electrochemical characterization of chemical species formed during the electrochemical treatment of chalcopyrite in sulfuric acid|journal=[[Electrochimica Acta]]|volume=51|issue=25|pages=5295–5303|doi=10.1016/j.electacta.2006.02.005}}</ref> Uses of covellite CuS superconductivity research can be seen in [[Lithium battery|lithium batteries]]’ [[cathode]]s, [[ammonium]] [[gas sensors]], and [[Solar electric|solar electric devices]] with metal [[chalcogenide]] thin films.<ref>{{Cite journal|last1=Chung|first1=J.-S.|last2=Sohn|first2=H.-J.|date=June 2002|title=Electrochemical behaviors of CuS as a cathode material for lithium secondary batteries|journal=Journal of Power Sources|volume=108|issue=1–2|pages=226–231|doi=10.1016/s0378-7753(02)00024-1|issn=0378-7753|bibcode=2002JPS...108..226C}}</ref><ref>{{Cite journal|last1=Sagade|first1=Abhay A.|last2=Sharma|first2=Ramphal|date=July 2008|title=Copper sulphide (CuxS) as an ammonia gas sensor working at room temperature|journal=Sensors and Actuators B: Chemical|volume=133|issue=1|pages=135–143|doi=10.1016/j.snb.2008.02.015|issn=0925-4005}}</ref><ref>{{Cite journal|last1=Mane|first1=R. S.|last2=Lokhande|first2=C. D.|date=2010-06-03|title=ChemInform Abstract: Chemical Deposition Method for Metal Chalcogenide Thin Films|journal=ChemInform|volume=31|issue=34|pages=no|doi=10.1002/chin.200034236|issn=0931-7597}}</ref>

===Lithium ion batteries===

Research into alternate cathode material for [[lithium batteries]] often examines the complex variations in stoichiometry and [[Tetrahedron packing|tetrahedron]] layered structure of copper sulfides.<ref>{{Cite journal|last1=Foley|first1=Sarah|last2=Geaney|first2=Hugh|last3=Bree|first3=Gerard|last4=Stokes|first4=Killian|last5=Connolly|first5=Sinead|last6=Zaworotko|first6=Michael J.|last7=Ryan|first7=Kevin M.|date=2018-03-24|title=Copper Sulfide (Cu x S) Nanowire‐in‐Carbon Composites Formed from Direct Sulfurization of the Metal‐Organic Framework HKUST‐1 and Their Use as Li‐Ion Battery Cathodes|journal=Advanced Functional Materials|volume=28|issue=19|pages=1800587|doi=10.1002/adfm.201800587|s2cid=104176144 |issn=1616-301X}}</ref> Advantages include limited toxicity and low costs.<ref name=":02">{{Cite journal|last1=Zhou|first1=Mingjiong|last2=Peng|first2=Na|last3=Liu|first3=Zhen|last4=Xi|first4=Yun|last5=He|first5=Huiqiu|last6=Xia|first6=Yonggao|last7=Liu|first7=Zhaoping|last8=Okada|first8=Shigeto|date=February 2016|title=Synthesis of sub-10 nm copper sulphide rods as high-performance anode for long-cycle life Li-ion batteries|journal=Journal of Power Sources|volume=306|pages=408–412|doi=10.1016/j.jpowsour.2015.12.048|bibcode=2016JPS...306..408Z|issn=0378-7753}}</ref> The high [[electrical conductivity]] of covellite (10−3 S cm−1) and a high theoretical [[Capacity factor|capacity]] (560 mAh g−1) with flat discharge curves when cycled versus Li+/Li has been determined to play critical roles for capacity.<ref name=":02" /> The variety of methods of formations is also a factor of the low costs. However, issues with cycle stability and [[Chemical kinetics|kinetics]] have been limiting the progress of utilizing covellite in mainstream lithium batteries until future developments in its research.<ref name=":02" />

=== Nanostructures ===
The [[electron mobility]] and free hole density characteristics of covellite makes it an attractive choice for [[Nanostructure|nanoplatelets]] and nanocrystals because they provide the structures the ability to vary in size.<ref name=":03">{{Cite journal|last1=Liu|first1=Yang|last2=Zhang|first2=Hanguang|last3=Behara|first3=Pavan Kumar|last4=Wang|first4=Xiaoyu|last5=Zhu|first5=Dewei|last6=Ding|first6=Shuo|last7=Ganesh|first7=Sai Prasad|last8=Dupuis|first8=Michel|last9=Wu|first9=Gang|date=2018-11-19|title=Synthesis and Anisotropic Electrocatalytic Activity of Covellite Nanoplatelets with Fixed Thickness and Tunable Diameter|journal=ACS Applied Materials & Interfaces|volume=10|issue=49|pages=42417–42426|doi=10.1021/acsami.8b15895|pmid=30451490|s2cid=206495105|issn=1944-8244}}</ref><ref name=":12">{{Cite journal|last1=Liu|first1=Maixian|last2=Xue|first2=Xiaozheng|last3=Ghosh|first3=Chayanjit|last4=Liu|first4=Xin|last5=Liu|first5=Yang|last6=Furlani|first6=Edward P.|last7=Swihart|first7=Mark T.|last8=Prasad|first8=Paras N.|date=2015-04-03|title=Room-Temperature Synthesis of Covellite Nanoplatelets with Broadly Tunable Localized Surface Plasmon Resonance|journal=Chemistry of Materials|volume=27|issue=7|pages=2584–2590|doi=10.1021/acs.chemmater.5b00270|issn=0897-4756}}</ref> However, this ability can be limited by the plate-like structure all copper sulfides possess.<ref name=":03" /> Its [[Anisotropy|anisotropic]] electrical conductivity has been experimentally proven to be greater within layers (i.e. perpendicular to c-axis).<ref name=":03" /> Researchers have shown that covellite nanoplatelets of approx. two&nbsp;nm thick, with one unit cell and two copper atoms layers, and diameters around 100&nbsp;nm are ideal dimensions for [[electrocatalyst]]s in [[oxygen reduction reaction]]s (ORR).<ref name=":03" /> The basal planes experience preferential oxygen adsorption and larger surface area facilitates electron transfer.<ref name=":03" /> In contrast, with ambient conditions, nanoplatelets of dimensions of four&nbsp;nm width and greater than 30&nbsp;nm diameter have been experimentally synthesized with less cost and energy.<ref name=":12" /> Conversely, [[localized surface plasmon resonance]]s observed in covellite [[nanoparticle]]s have recently been linked to the [[stoichiometry]]-dependent [[band gap]] key for nanocrystals.<ref name=":2">{{Cite journal|last1=Xie|first1=Yi|last2=Riedinger|first2=Andreas|last3=Prato|first3=Mirko|last4=Casu|first4=Alberto|last5=Genovese|first5=Alessandro|last6=Guardia|first6=Pablo|last7=Sottini|first7=Silvia|last8=Sangregorio|first8=Claudio|last9=Miszta|first9=Karol|date=2013-11-06|title=Copper Sulfide Nanocrystals with Tunable Composition by Reduction of Covellite Nanocrystals with Cu+ Ions|journal=Journal of the American Chemical Society|volume=135|issue=46|pages=17630–17637|doi=10.1021/ja409754v|pmid=24128337|issn=0002-7863}}</ref><ref>{{Cite journal|last1=Xie|first1=Yi|last2=Bertoni|first2=Giovanni|last3=Riedinger|first3=Andreas|last4=Sathya|first4=Ayyappan|last5=Prato|first5=Mirko|last6=Marras|first6=Sergio|last7=Tu|first7=Renyong|last8=Pellegrino|first8=Teresa|last9=Manna|first9=Liberato|date=2015-10-29|title=Nanoscale Transformations in Covellite (CuS) Nanocrystals in the Presence of Divalent Metal Cations in a Mild Reducing Environment|journal=Chemistry of Materials|volume=27|issue=21|pages=7531–7537|doi=10.1021/acs.chemmater.5b03892|pmid=26617434|issn=0897-4756|pmc=4652895}}</ref> Thus, future chemical sensing devices, electronics, and others instruments are being explored with the use of nanostructures with covellite CuS.<ref name=":03" /><ref name=":2" />