Can domestic wastes-evolved Fe₂N@Carbon hybrids serve as competitive anodes for sustainable Li/Na storage applications?

Evolution of domestic wastes into competitive battery materials at less expense is a rational strategy of "killing two birds with one stone", and never better for grid-scale energy-storage utilizations wherein achieving great energy density is less crucial than environmental friendliness and cost. To checkout this concept, we herein select Fe₂N, a conductive conversion-type anode for Li-/Na-ion batteries (LIBs/SIBs), as a paradigm study. Rusty/plastic wastes-evolved anodes with a proper tap density of 1.74 g cm⁻³ are composed of numerous nanoparticles where each Fe₂N unit is evenly configured in robust carbon sheath. Such electrodes demonstrate impressive specific capacities under varied areal mass loading ratios of 3∼15 mg cm^-2, outstanding rate capabilities and cyclic stability. To judge their promise in practical usage, we successively choose economical LiFePO₄ and phase-stable Na₃V₂(PO₄)₃ as pairing cathodes to build full-cell LIBs/SIBs. This wastes-to-battery protocol may pave a way to advance practical techniques for sustainable usage beyond.