Pursuing an alternate energy-savvy synthetic route for economic synthesis of polyanionic cathode materials, we have developed a splash combustion synthesis method. It is capable of producing Fe(II) based cathodes starting from cheap Fe(III) precursors under a quick 1-minute high-temperature annealing step. The proof-ofconcept test was carried out on Li2FeP2O7 cathode with success in achieving nanoscale, carbon-coated end-product with reversible discharge capacity of 100 mAh/g. Further, exploiting this synthetic method, we have discovered a novel Na2FeP2O7 cathode with promising electrochemical properties for rechargeable sodium-ion batteries. The details of splash combustion synthesized alkali metal pyrophosphate cathodes are described in a nutshell.