Chitosan is a naturally occurring polysaccharide with abundant biomass resources that attracts interest due to its unique physicochemical properties. The importance of chitosan has risen recently (a) because it is a renewable and biodegradable material and (b) because it has the ability to form a membrane. Therefore, chitosan is highly preferable for green energy applications. This review describes the most recent advancements in chitosan chemistry, emphasizing elemental modifying reactions like sulfonation, phosphorylation, phthaloylation, and chemical cross-linking. However, the major issues of the chitosan (CS)-based polymer electrolyte membrane (PEM) are attaining high proton conductivity, leakage across fuel cells, and durability. To overcome the above-mentioned issues, chitosan and the emerging class of inorganic materials 2-D transition metal dichalcogenides especially MoS 2 can be employed for proton-exchange membrane fuel cell applications. Surface functionalization of MoS 2 can open new pathways for fabricating CS/MoS 2 composite membranes. Current research also focuses on the following issues: (a) strategies for the development of PEM, (b) properties and structures of chitosan for fuel cell applications, and (c) chitosan utilization in different parts of the fuel cell. The present study also discusses progress and particular challenges that chitosan-based proton exchange membranes face. Moreover, strategies to control those issues and future aspects are discussed in detail.

No abstract

A one-step method was enforced for the phosphorylation of chitosan (CS) using ATMP, and later amino-functionalized multi-walled carbon nanotubes (MWCNTs-NH2) were used for the fabrication of PCS/N-MWCNTs membranes. The phosphorylation of CS and later PCS/N-MWCNTs nanocomposite membranes were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy. They were also evaluated for their mechanical properties, water uptake, area swelling ratio, ion-exchange capacity (IEC), and proton conductivity. Interfacial interaction among an -NH2 group of MWCNTs and -phosphonic acid as well as the -NH2 group of PCS provided extra sites for proton transfer, thus improving the proton conductivity of PCS/N-MWCNTs membranes. These results revealed that the incorporation of N-MWCNTs into PCS chains lowers PCS chain mobility and ultimately improved the thermal and mechanical properties of the composite membranes. The proton conductivity of the composite membrane with 5 wt. % of N-MWCNTs at 80°C was 0.045 S.cm−1. Thus, PCS/N-MWCNTs nanocomposite membranes as a PEM can be used in fuel cells. With this advantage, the N-MWCNTs-filled hydrogen fuel cell outperforms compared to PCS filled membrane.

Abstract-Electricity generation by single-chamber air cathode fuel cells (MFCs) is considerably influenced by power management system(PMS). This study showed that application of PMS connected with a single-chamber air cathode MFC significantly improved its columbic efficiencies (CEs), current, and power output. In MFC tests based on PMS, the optimal COD of influent was 400 mg/L, achieving the highest CE (4.59%) and the optimal COD of influent 800 mg/L with the highest harvesting efficiency(9.80%), which were higher than those in MFCs connecting resistors. The ranges of voltage output and power out of MFC based on PMS were 1.60 ~ 2.00 V, 2.56 ~ 4.00 mW, higher than those in MFCs with resistors, while low COD prolonged charge time. PMS improved MFC performance, and both of the electricity generation of MFC and the harvesting efficiency should be considered.