text: There are other LISICON type solid electrolytes which make use of other elements to achieve higher ionic conductivities.  One such material has the chemical formula of LiGeVO, where the value of x is between 0 and 1. There are two compositions, LiGeVO and LiGeVO, which had ionic conductivities of 4*10 S/cm and 10 S/cm, an order of magnitude of improvement upon the base LISICON structure.  These materials show good thermal stability and are stable in contact with CO and ambient atmosphere, dealing with some problems extant with the original structure.
  There are materials with the chemical structure of LiSiPO.  This is a solid solution between LiSiO and LiPO.  This solid solution can be formed over the whole composition range at room temperature.  The highest ionic conductivity are achieved at compositions of LiSiPO and LiSiP, with conductivity on the order of 10 S/cm.  This results from the substitution of some Si for P in the lattice, resulting in the addition of interstitial Li-ions which diffuse much more easily.  The ionic conductivity is further improved with the doping of Cl to replace O in the lattice.  The compositions LiSiPCl and LiGePCl achieved ionic conductivities of 1.03 * 10 S/cm and 3.7*10 S/cm respectively.  This is theorized to be the due to the widening of the “bottlenecks” between interstitial points due to the Cl ions smaller size, and the weakening of the ionic bonding Li ions experienced due to chlorine's lower electronegativity.
  The conductivities are almost 100 times higher in thio-LISICONs, where oxygen is replaced by sulfur, i.e. the corresponding thiosilicates.  The bonding between S and Li is weaker than that between O and Li, allowing for the Li in the sulfide structure to be far more normal than its oxide counterparts.  Ceramic thio-LISCON materials based on the chemical formula LiGePS are promising electrolyte materials, with ionic conductivities on the order of 10 S/m or 10 S/m.