The ambient temperature structure of Cu4SnS4 has been revisited and the low temperature structure has been determined. A structural phase transition from a large monoclinic unit cell to smaller orthorhombic unit cell in transitioning from low to high temperature has been observed. The room temperature phase exhibit disorder in the two copper sites, which is a different finding from earlier report. The low temperature monoclinic form crystallizes in P21/c spacegroup, which is isostructural with Cu4GeS4. The phase transition has also been studied with variable temperature powder X-ray diffraction. The Seebeck coefficients, electrical resistivity, and thermal conductivity of polycrystalline Cu4SnS4 were measured from 2 to 700 K on hot pressed pellets. In all the transport measurements the phase transition has been observed at around 229 K. Resistivity decreases, while Seebeck coefficient increases after the phase transition in transitioning from low temperature to high temperature. This change in resistivity has been correlated from the electronic band structure calculation. Cu4SnS4 is also capable of hosting lithium ions through reductive lithium intercalation both chemically and electrochemically and, therefore, can act as an electrode material for Li-ion batteries.

New insights into the structure, properties, and chemistry of Cu4SnS4

251st National Meeting (2016)

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