Tin-Based Oxide, Alloy, and Selenide Li-Ion Battery Anodes Derived from a Bimetallic Metal-Organic Material

Here we report the formation of three distinct Sn-based active materials for Li-ion battery anodes, formed from the same metal-organic material (MOM) precursor sql-1-Cu-SNIFSIX. The materials were obtained under three different anneal conditions in air, Ar, and a Se-rich atmosphere, leading to the selective formation of SnO2/CuO/C (oxide), Cu6Sn5/C (stannide), and Cu2SnSe3/SnSe2/C (selenide) composites. The lithiation and delithiation mechanisms were investigated for each material in the potential range of 0-3 V. Over extended cycling periods, the reversible alloying of Li with Sn was the only process evident for the stannide, with minimal activity occurring at potentials greater than 1 V. In contrast to this, the oxide and selenide composites exhibit both conversion (1-3 V) and Li/Sn alloying (0-1 V) behavior in this potential range; however, the stability of the conversion reaction was found to be poor, inhibiting the capacity retention of both materials. Notably, when the reaction mechanisms were restricted to Li/Sn alloying only by limiting the potential range to 0-1 V, all three composite materials significantly outperformed a Sn nanopowder electrode, illustrating the benefits of utilizing composite electrodes to stabilize the Sn alloying reaction over extended cycling periods.

Automated summary

Three distinct Sn-based active materials were formed for Li-ion battery anodes from the same metal-organic material precursor, with the stannide material showing the best stability during alloying. However, the oxide and selenide composites exhibited poor stability due to the conversion reaction hindering capacity retention. Using a limited potential range of 0-1 V for Li/Sn alloying showed superior performance of all three composite materials compared to a Sn nanopowder electrode, indicating the benefits of utilizing composite electrodes to stabilize the Sn alloying reaction over extended cycling periods.