“energy” is marked as the top notch global issue facing this 21st century. the mantra to solve the issue is comprised in three words: generation, storage and supply. in this regard, energy storage is at the heart of everything that connects generation from alternate energy sources like solar, wind, waves, nuclear, geothermal etc. to a gasoline free supply. among all storage sectors, electrochemical storage or in particular rechargeable secondary batteries offers the most versatile, economic and sustainable solution. advances in this particular rechargeable batteries also addresses country’s most crucial problem of greenhouse effect by realizing the use of electric vehicles. in rechargeable battery category the most common name or can say the only name known to most of the people is li-ion batteries. ever since the commercialization of li-ion batteries by sony in 1991, they have grown leaps and bounds over the last two decades by empowering portable electronics, (plug-in) hybrid electric vehicles, remote area large-scale grid power storage, and storage devices coupled with renewable energy generators (e.g.,solar cells). on the other side, this manifold consumption of lithium also led to scarcity and geo political tension. what next for the power hungry needs of ever growing population!!! lithium batteries are nearing their limits and most researchers that li-ion cells will never give electric cars the 800-kilometre range of a petrol tank, or supply power-hungry smartphones with many days of juice. at this time there is a surge to go beyond lithium ion. while portable electronics and electric vehicle applications depends hugely on the chemistry of li ions for their small size and energy density: chemistry of more abundant na ions can excel or serve better for economically viable large-scale applications (e.g., remote grid storage) without any volume restriction. this has motivated the energy community to go big for the grid with na ion. among all the components of batteries, cathode constitutes the highest 33 percent of the production cost (nedo report-2015). realizing that, the next generation batteries rely on developing superior cathodes which combines low cost and high energy-density obtained materials with high theoretical capacity and/or high redox voltage, we bring the highest ever redox voltage and energy density in na ion league : the alluaudite class (na2m2(so4)3 ; m: fe, co, mn ) of sodium ion positive insertion materials. previously, na ion used to take the back seat running behind li-ion because of its bigger size leading to sluggish kinetics. then the first report on na2fe2(so4)3 (family-alluaudite) came with the highest ever 3.8v (against na), even exceeding the highest record in the li system. taking the study forward, i have looked in to the reported synthesis approach involving (a) formation of anhydrous feso4 from commercial feso4.7h2o, (b) prolonged milling and (c) longer annealing (350°c, 24 h). journey of such materials from laboratory to industry warrants economic, sustainable and scalable synthesis. here, we report novel solution assisted- ionothermal , aqueous spray-drying and pechini synthesis of na2fe2(so4)3, [m = 3d metals] alluaudite cathodes. solution assisted synthesis has advantage over reported solid state synthesis in means of reducing time or temperature or both, since diffusion of ions in liquid is faster than solid. so i could achieve the synthesis at lowest ever 6h time. further i could reduce the synthesis of this superior cathode materials’ temperature up to 150o c with pechini method, the temperature at which water boils. this can be at the edge of commercialization for the same material. next employing the inductive effect i further marked two new materials na2.44mn1.79(so4)3, na2.37co1.83(so4)3 having working potential of 4.4 v and 5v respectively which defines the frontiers for next generation secondary batteries.