Rational Design and Engineering of 1D Heterostructured Porous Sn/CoSnX@C Nanotubes for Superior Lithium Storage

Tin is a good anode material for lithium storage because of its high theoretical capacity and good conductivity, but large volume changes during the charging/discharging process lead to poor rate performance and cycling stability. In this work, by assembling ZIF-67 nanosheets on SnO2@PDA nanotubes and following a calcination process, heterostructured Sn/CoSnx (x = 1, 2) alloy anchored N-doped porous carbon nanotubes with high lithium storage performance were rationally designed and successfully prepared (Sn/CoSnx@C). The Co incorporated in CoSnx intermetallic can buffer the internal stress, and combined with the porous structure, the large volume expansion can be effectively alleviated. Besides, coating the ultrafine Sn/CoSnx crystals within one-dimensional N-doped carbon can inhibit particle agglomeration, thus enhancing cyclic stability. Moreover, benefiting from the porous tubular structure that can shorten the mass/charge transport distance, the generated abundant heterointerfaces can promote reaction kinetics, achieving improved rate capacity. Therefore, the tubular structured Sn/CoSnx@C anode shows a high reversible specific capacity of 1713.2 mAh g-1 at a current density of 100 mA g-1, a high rate performance of 1394.1 mAh g-1 at 1.0 A g-1 and 1051.3 mAh g-1 at 5.0 A g-1, and an excellent cycling stability of 444.3 mAh g-1 at 5 A g-1 over 5000 cycles. These results demonstrate an effective strategy for developing high-performance metal alloy-based electrodes in the energy storage system.

Automated summary

In this work, Sn/CoSnx (x = 1, 2) alloy anchored N-doped porous carbon nanotubes were designed and prepared for high lithium storage performance. The incorporation of Co in CoSnx can buffer internal stress and alleviate volume expansion, while coating the Sn/CoSnx crystals in N-doped carbon inhibits particle agglomeration and enhances cyclic stability. The tubular structured Sn/CoSnx@C anode exhibits a high reversible specific capacity, excellent rate performance, and cycling stability, indicating its potential in energy storage systems.