Microbial reduction of graphene oxide and its application in microbial fuel cells and biophotovoltaics

Despite more than a decade of study,there are still significant obstacles to overcome before graphene can be successfully produced on a large scale for commercial use.Chemical oxidation of graphite to produce graphene oxide(GO),followed by a subsequent reduction process to synthesize reduced graphene oxide(rGO),is considered the most practical method for mass production.Microorganisms,which are abundant in nature and inexpensive,are one of the potential green reductants for rGO synthesis.However,there is no recent review discussing the reported microbial reduction of GO in detail.To address this,we present a comprehensive review on the reduction of GO by a range of microorganisms and compared their efficacies and reaction conditions.Also,presented were the mechanisms by which microorganisms reduce GO.We also reviewed the recent advancements in using microbially reduced GO as the anode and cathode material in the microbial fuel cell(MFC)and algal biophotovoltaics(BPV),as well as the challenges and future directions in microbial fuel cell research.

Poly(m-phenylene isophthalamide)-reinforced polyethylene oxide composite electrolyte with high mechanical strength and thermostability for all-solid-state lithium metal batteries

Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with flexibility,easy processability,low cost and especially strong ability to dissolve lithium salts have been regarded as promising alternatives to traditional flammable liquid electrolytes in next-generation highsafety and high-energy-density lithium metal batteries.However,the inferior mechanical strength and thermostability of PEO-based SPEs will raise the lithium dendritic penetration issue,further leading to the short circuit in batteries.In this work,aiming at enhancing the interfacial stability against Li dendrites of PEO-based SPEs,poly(mphenylene isophthalamide)(PMIA)is introduced as a reinforcing phase for the rational design of PEO/PMIA composite electrolyte.Impressively,PMIA chain with meta-type benzene-amide linkages significantly improves the mechanical strength(1.60 MPa),thermal stability(260℃)and ability to inhibit the growth of lithium dendrites(>300 h at 0.1 mA·cm^(-2))of SPEs.Meanwhile,allsolid-state LiFePO_(4)‖PEO/PMlA‖Li cell demonstrates superior electrochemical performance in terms of high specific capacity(159.1 mAh·g^(-1)),remarkable capacity retention(82.2%after 200 cycles at 0.5 C)and excellent safety characteristics.No burning or explosion occurs under pressing,bending and cutting conditions.This work opens a new door in developing high-performance PEObased electrolytes for advanced all-solid-state lithium metal batteries.