Microelectrodes fabricated by etching techniques. (A) The fabrication process of the Zn-Br₂ microbatteries and (B) in situ construction of Br₂ cathode and Zn anode during the charging process [43]. (C) Schematically illustration of the fabrication of the MnO₂ Swiss-roll microelectrode and MnO₂ Swiss-roll-based microbattery [50]. (D) Schematic diagram of a ZMSC after interlayer Zn^δ+ atomic injection and the incorporation of battery-type voltage plateau [60]. Reproduced with permission.