Editing Fuel cell (section)

===Biofuel cell===
{{Main article|Microbial fuel cell|Enzymatic biofuel cell}}
A biofuel cell converts chemical energy from biological substances into electrical energy using biological catalysts, such as enzymes or microorganisms. The process involves the oxidation of a fuel, like glucose, at the anode, releasing electrons and protons. The electrons travel through an external circuit to generate electrical current, while at the cathode, oxygen is typically reduced to water or hydrogen peroxide, completing the circuit.<ref>{{cite journal |last1=Huang |first1=Wengang |last2=Zulkifli |first2=Muhammad Yazid Bin |last3=Chai |first3=Milton |last4=Lin |first4=Rijia |last5=Wang |first5=Jingjing |last6=Chen |first6=Yuelei |last7=Chen |first7=Vicki |last8=Hou |first8=Jingwei |title=Recent advances in enzymatic biofuel cells enabled by innovative materials and techniques |journal=Exploration |date=August 2023 |volume=3 |issue=4 |doi=10.1002/EXP.20220145|pmid=37933234 |pmc=10624391 }}</ref> Applications include wastewater treatment and renewable energy production.<ref>{{cite journal |last1=Babanova |first1=Sofia |title=Biofuel Cells – Alternative Power Sources |journal=International Scientific Conference (FMNS2013), Blagoevgrad (Bulgaria) |date=2009 |url=https://inis.iaea.org/records/4884q-dkm61 |language=en}}</ref> Conductive polymers may be used to improve electron transfer between enzymes and electrodes.
<ref>{{cite journal |last1=Kižys |first1=Kasparas |last2=Zinovičius |first2=Antanas |last3=Jakštys |first3=Baltramiejus |last4=Bružaitė |first4=Ingrida |last5=Balčiūnas |first5=Evaldas |last6=Petrulevičienė |first6=Milda |last7=Ramanavičius |first7=Arūnas |last8=Morkvėnaitė-Vilkončienė |first8=Inga |title=Microbial Biofuel Cells: Fundamental Principles, Development and Recent Obstacles |journal=Biosensors |date=3 February 2023 |volume=13 |issue=2 |pages=221 |doi=10.3390/bios13020221|doi-access=free |pmid=36831987 |pmc=9954062 }}</ref>

The integration of nanomaterials, such as carbon nanotubes and metal nanoparticles, are used to enhance the performance of BFCs. These materials increase the surface area of electrodes and facilitate better electron transfer, resulting in higher power densities. Three-dimensional porous structures and graphene-based materials, have been used to improve conductivity and stability, and hybrid biofuel cells that combine BFCs with supercapacitors or secondary batteries are being developed to provide stable and continuous energy output.<ref>{{cite journal |last1=Kwon |first1=Cheong Hoon |last2=Ko |first2=Yongmin |last3=Shin |first3=Dongyeeb |last4=Kwon |first4=Minseong |last5=Park |first5=Jinho |last6=Bae |first6=Wan Ki |last7=Lee |first7=Seung Woo |last8=Cho |first8=Jinhan |title=High-power hybrid biofuel cells using layer-by-layer assembled glucose oxidase-coated metallic cotton fibers |journal=Nature Communications |date=26 October 2018 |volume=9 |issue=1 |doi=10.1038/s41467-018-06994-5|pmc=6203850 }}</ref> BFCs are being explored as power sources for implantable devices like pacemakers and biosensors.to potentially eliminate the need for traditional batteries, and fiber-type EBFCs show potential in implantable applications.<ref>{{cite journal |last1=Cai |first1=Jingsheng |last2=Shen |first2=Fei |last3=Zhao |first3=Jianqing |last4=Xiao |first4=Xinxin |title=Enzymatic biofuel cell: A potential power source for self-sustained smart textiles |journal=iScience |date=February 2024 |volume=27 |issue=2 |pages=108998 |doi=10.1016/j.isci.2024.108998|pmc=10850773 }}</ref> The power density of BFCs, however, is generally lower than that of conventional energy sources, the stability of enzymes and microorganisms over extended periods is another concern, and scalability and commercial viability also pose hurdles.<ref>{{cite journal |last1=Wang |first1=Linlin |last2=Wu |first2=Xiaoge |last3=Su |first3=B. S. Qi‐wen |last4=Song |first4=Rongbin |last5=Zhang |first5=Jian-Rong |last6=Zhu |first6=Jun-Jie |title=Enzymatic Biofuel Cell: Opportunities and Intrinsic Challenges in Futuristic Applications |journal=Advanced Energy and Sustainability Research |date=August 2021 |volume=2 |issue=8 |doi=10.1002/aesr.202100031|doi-access=free }}</ref>