Spark Plasma Sintering (SPS) offers advantages that include faster densification, activated materials synthesis, formation of atomically clean grain boundaries, good grain-to-grain bonding, and minimization of particle coarsening that allows the retention of nanosized grains/particles during synthesis or sintering. The present review summarizes for the first time the possibilities of using these advantages for applications in electrochemical energy storage, or more precisely, for developing high performance all-solid-state Li-ion batteries that are better suited for more heavy duty applications, such as in automobiles. This survey demonstrates the improvements that can be achieved for the ionic conductivities of the ceramic solid electrolytes on sintering via SPS and for the overall transport properties of the cathode materials on synthesizing via SPS. These would not only render the solid electrolytes better suited for enhanced practical applications, but also result in overall improved rate capabilities for the batteries. Furthermore, possibilities of fabricating entire solid-state Li-ion batteries, possessing improved mechanical integrity and power density, via one-step SPS of stacked laminates of anode–solid electrolyte–cathode materials have been brought into light. The improvements achieved, mainly due to the formation of ‘perfect’ interfaces and due to nanostructuring, are correlated to the intrinsic mechanisms of the spark plasma sintering process.