Nanoarchitectured LiMn sub(2)O sub(4)/Graphene/Zn0 Composites as Electrodes for Lithium Ion Batteries

LiMn sub(2)O sub(4) nanoparticles are facilely synthesized using a sol-gel processing method. Graphene is added to LiMn sub(2)O sub(4) electrode aiming at increasing specific capacity and improving rate capability. In order to further improve cycling stability of LiMn sub(2)O sub(4)/graphene electrode, atomic layer deposition (ALD) is used to deposit ultrathin ZnO coating composed of six ZnO ALD layers and modify the surface of either LiMn sub(2)O sub(4)/graphene electrode or individual LiMn sub(2)O sub(4) particles to form nanoarchitectured LiMn sub(2)O sub(4)/graphene/ZnO electrodes. Both ZnO-ALD-modified LiMn sub(2)O sub(4)/graphene electrodes demonstrate enhanced cycling performance at 1 C, retaining the final discharge capacity above 122 mA h g super(-1) after 100 electrochemical cycles, which is higher than 115 mA h g super(-1) of pristine LiMn sub(2)O sub(4)/graphene electrode and 109 mA h g super(-1) of bare LiMn sub(2)O sub(4) electrode. The improved electrochemical performance of nanoarchitectured LiMn sub(2)O sub(4)/graphene/ZnO electrodes can be attributed to the cooperative effects from high electronic conductivity of graphene sheets to facilitate electron transportation and effective protection of ZnO ALD coating to restrict Mn dissolution and electrolyte decomposition.