1. A resistive switching device, comprising: a first electrode comprising a first metal material; a second electrode comprising at least a second metal material; a switching material, the switching material comprising a non-conductive material having non-stoichiometric sites, wherein the non-stoichiometric sites are configured to trap metal particles of the second metal material derived from the second electrode therein; and a buffer material disposed between the first electrode and the switching material and completely separating the first electrode and the switching material, the buffer material providing a blocking region between the switching material and the first electrode, the blocking region being substantially free from the metal particles from the second metal material when a first voltage is applied to the second electrode.