Polynuclear superhalogen anion Li12F13 − and its ionic complexes formed by the interaction with selected metal ions (i.e., Li12F13 −Na+, Li12F13 −K+, Li12F13 −Mg2+, and Li12F13 −Zn2+) are proposed and investigated on the basis of ab initio calculations. The thermodynamic stability, vertical excess electron detachment energy, and binding energies between ionic components were examined and discussed. The Li12F13 − anion has been proved stable against fragmentation and its vertical electronic stability was found to approach 10 eV. Due to its specific equilibrium structure that resembles a molecular basket, the Li12F13 − anion was found capable of trapping positively charged metal ions inside to form strongly bound ionic complexes. The large values of binding energies predicted for the Li12F13 −Na+, Li12F13 −K+, Li12F13 −Mg2+, and Li12F13 −Zn2+ systems and their specific equilibrium structures indicate that the Li12F13 − anion can be useful as a steric shielding system which protect the metal ions from the interaction with the surroundings.