Microbial fuel cells (MFCs) that generate electricity generation from a broad diversity of biomass and organic substrates through microbial metabolism, have attracted considerable research interest as an alternative clean energy technology and energy-efficient wastewater treatment method. Despite encouraging successes and auspicious pilot-scale experiments of the MFCs, increasing doubts about their viability for practical large-scale applications are being raised. Low performance, expensive core parts and materials, energy-intensive operation, and scaling bottlenecks question a sustainable development. Instead, special MFCs for low-power battery-reliant devices might be more applicable and potentially realizable. Such bacteria-powered biobatteries would enable (i) a truly stand-alone device platform suitable for use in resource-limited and remote regions, (ii) simple, on-demand power generation within a programmed period of time, and (iii) a tracelessly biodegradable battery due to the use of the bacteria used for power generation. The biobattery would be an excellent power solution for small-scale, on-demand, single-use, and disposable electronics. Recent progress of small-scale MFCbased biobatteries is critically reviewed with specific attention toward various device platforms. Furthermore, comments and outlook related to the potential directions and challenges of the biobatteries are discussed to offer inspiration to the community and induce fruitful future research. pack. A) Reproduced with permission.