Journal Article direct regeneration battery recycling Review cathode materials lithium‐ion batteries FeO bonding Li replenishment channels LiFePO4 N-doped Ni‐rich cathode material all solid-state Li-metal batteries amino acid band structure closed‐loop degradation mechanism direct repair direct upcycling electrolyte engineering element doping elevated d-band centers fluorinated solid electrolyte interphase heterogeneous interfaces high current density high energy density high-voltage LiCoO2 high‐voltage homogeneous repair hydrometallurgy interface stabilization