Carbon-wrapped core-shell nanospheres of tin-graphitized carbon for superior lithium-ion battery

A simple strategy of controllable pyrolysis of metal-organic framework has been developed for the synthesis of carbon wrapped core-shell nanospheres of tin-graphitized carbon hybrid. This hybrid electrode exhibits superior electrochemical properties, achieving remarkable capacities of 550 and 430 mA h g−1 over 200 cycles at 0.5 and 1.0 A g−1, respectively. The carbon matrix can buffer large volume variations of tin during lithium/delithium process and can avoid the electrode pulverization, resulting in outstanding cycling stability. The graphitized carbon shell and tin nanocrystals core could enhance the electrode conductivity and provide large electrode/electrolyte contact areas, leading to a high reversible capacity.