Abstract
Among the promising high capacity anode materials, tin dioxide (SnO2) represents a classic and important candidate that involves both conversion and alloying reactions toward Li storage. However, the inferior reversibility of conversion reactions usually results in low initial Coulombic efficiency (ICE, ~ 60%), small reversible capacity and poor cycling stability of electrodes. Here, we demonstrate that by carefully designing the interface structure of SnO2-Mo, a breakthrough comprehensive performance with ultrahigh average ICE up to 92.6 %, large capacity of 1067 mA h g-1 and 100 % capacity retention after 200 cycles can be realized in a multilayer Mo/SnO2/Mo electrode. The amorphous SnO2/Mo interfaces, which are induced by redistribution of oxygen atoms between SnO2 and Mo, can precisely adjust the reversible capacity and cycling stability of the multilayers, while the stable capacities of electrodes are parabolic with the interfacial density. Theoretical calculations and in/ex-situ experimental investigation clearly reveal that oxygen redistribution in the SnO2/Mo hetero-interfaces boosts the Li ions transport kinetics by inducing a built-in electric field and improves the reaction reversibility of SnO2. This work provides a new understanding of the interface-performance relationship of metal-oxide hybrid electrodes and pivotal guidance for creating high performance Li-ion batteries.
Achieving over 90 % initial Coulombic efficiency and highly stable Li storage in SnO2 by constructing interfacial oxygen redistribution in multilayers