Synthesis and Electrochemical Properties of Amorphous Carbon Coated Sn Anode Material for Lithium Ion Batteries and Sodium Ion Batteries.

Sn is one of the promising anode material for lithium-ion and sodium-ion batteries because of Sn has many advantages such as a high theoretical capacity of 994 mAh/g, inexpensive, abundant and nontoxic. However, Sn-based anodes have a critical problem from pulverization of the particles due to large volume change (>300% in lithium-ion battery and 420% in the sodium-ion battery) during alloying/dealloying reaction. To overcome this problem, we fabricate Sn/C particle of core/shell structure. Sn powder was produced by pulsed wire explosion in liquid media, and amorphous carbon coating process was prepared by hydrothermal synthesis. The charge capacity of Sn electrode and amorphous carbon coated Sn electrode was 413 mAh/g and 452 mAh/g after 40 cycles in lithium half-cell test. The charge capacity of Sn electrode and amorphous carbon coated Sn electrode was 240 mAh/g and 487 mAh/g after 40 cycles in sodium half-cell test. Amorphous carbon coating contributed to the improvement of capacity in lithium and sodium battery systems. And the effect of amorphous carbon coating in sodium battery system was superior to that in lithium battery system.

Electrochemical Behavior of Sn/Cu6Sn5/C Composite Prepared by Using Pulsed Wire Explosion in Liquid Medium for Lithium-Ion Batteries.

Tin-based materials, due to their high theoretical capacity of 994 mAh g-1 are potential candidates which can substitute the commercialized graphite anodes (372 mAh g-1). However, practical usage of pure tin in Li-ion cells has been hampered by the tremendous volume expansion of more than 260% during the lithium insertion/extraction process, resulting in particle pulverization and electrical disconnection from the current collector. In order to overcome this shortcoming, Sn/Cu6Sn5/C composites in this work were prepared by using pulsed wire explosion in a liquid medium and subsequently in situ polymerization. For comparison, Sn/C composite without tin-copper chemical compounds are also fabricated under a similar process. The Sn/Cu6Sn5/C and Sn/C composites were used as anodes for lithium-ion batteries. The Sn/Cu6Sn5/C composite anode showed good cyclability (scalability) and was maintained up to a capacity of 430 mAh g-1 after 100 cycles at 1 C-rate. The rate capability of the Sn/Cu6Sn5/C composite anode also showed higher performance (280 mAh g-1) than that (200 mAh g-1) of Sn/C composite at the 5 C-rate.