Oxygen-doped carbon host with enhanced bonding and electron attraction abilities for efficient and stable SnO2/carbon composite battery anode

The coupling between electrochemically active material and conductive matrix is vitally important for high efficiency lithium ion batteries (LIBs). By introducing oxygen groups into the nanoporous carbon framework, we accomplish sustainably enhanced electrochemical performance for a SnO2/carbon LIB. 2–5 nm SnO2 nanoparticles are hydrothermally grown in different nanoporous carbon frameworks, which are pristine, nitrogen- or oxygen-doped carbons. Compared with pristine and nitrogen-doped carbon hosts, the SnO2/oxygen-doped activated carbon (OAC) composite exhibits a higher discharge capacity of 1,122 mA h g−1 at 500 mA g−1 after 320 cycles operation and a larger lithium storage capacity up to 680 mA h g−1 at a high rate of 2,000 mA g−1. The exceptional electrochemical performance is originated from the oxygen groups, which could act as Lewis acid sites to attract electrons effectively from Sn during the charge process, thus accelerate reversible conversion of Sn to SnO2. Meanwhile, SnO2 nanoparticles are effectively bonded with carbon through such oxygen groups, thus preventing the electrochemical sintering and maintaining the cycling stability of the SnO2/OAC composite anode. The high electrochemical performance, low biomass cost, and facile preparation endows the SnO2/OAC composites a promising candidate for anode materials.