The global energy crisis and an increase in environmental pollution in the recent years have drawn the attention of the scientific community towards the development of efficient electrochemical devices. Polymers containing charged species have the potential to serve as electrolytes in next-generation devices and achieving high ion transport properties in these electrolytes is the key to improving their efficiency. In this article, we explore ways to improve the ion transport properties of solid polymer electrolytes by focusing on the use of ionic liquids (ILs). The application of IL-incorporated polymer electrolytes in lithium batteries, high temperature fuel cells, and electro-active actuators is summarized. For each system, the current level of understanding of the diverse factors affecting the transport properties of polymer electrolytes integrated with ILs is presented, in addition to the challenges encountered and strategies toward obtaining significantly improved device performances. The creation of self-assembled morphologies in IL-containing polymer electrolytes by the use of block copolymers is particularly highlighted as a novel prospective technique geared towards obtaining next-generation electrochemical devices with enhanced performances.

We present a facile synthetic route toward binder-free, highly-dispersed Ge nanoparticles in carbon matrices using one-step pyrolysis of self-assembled Ge-polymer hybrids. 3-Dimensionally arranged Ge-carbon exhibits remarkably enhanced cycling properties and rate capability compared with carbon sheathed Ge lacking organization.

We have explored new Li–polymer batteries composed of surface functionalized Si nanoparticles (SiNPs) as anode active materials and nanostructured block copolymers as solid electrolytes. Surface protection of SiNPs with poly(ethylene oxide) chains successfully prevents aggregation of SiNPs during cycling and also helps fast Li+ transport to the active centers in the anodes. The self-assembly nature of block copolymer electrolytes in ca. 50 nm periodicity is aimed to restrain the formation of macroscopic ionic clusters during Li-insertion/desertion. To decouple the electrical and mechanical properties of polymer electrolytes, two different nonvolatile additives (ionic liquid and non ionic plasticizer) were incorporated and remarkably different cycle performances have been observed. The incorporation of ionic liquid yields the utmost ionic conductivity and distinctly large first lithium insertion capacity of 2380 mA h/g was seen. However, the formation of solid electrolyte interphase (SEI) was responsible for highly irreversible lithium desertion capacity and the system indicate fast capacity fading during cycling. With the use of non ionic plasticizer, in contrast, the SiNPs anode can store lithium up to a reversible capacity of ∼1850 mA h/g under aggressive test profiles of 80 °C and voltage window between 0–4.5 V. The focused ion beam technique was successfully used to obtain ex-situ transmission electron microscopy images of cycled polymer electrolytes and anode materials to underpin the origin of capacity retention or fading upon cycling. The results suggest that the structural retention of both polymer electrolytes and SiNPs during cycling attributes to the improved battery performance.

We developed a new ratiometric pH sensor based on poly(N-phenylmaleimide) (PPMI)-containing block copolymer that emits three different fluorescent colors depending on the pH. The strong solvatochromism and tautomerism of the PPMI derivatives enabled precise pH sensing for almost the entire range of the pH scale. Theoretical calculations have predicted largely dissimilar band gaps for the keto, enol, and enolate tautomers of PPMI owing to low-dimensional conjugation effects. The tunable emission wavelength and intensity of our sensors, as well as the reversible color switching with high-luminescent contrast, were achieved using rational molecular design of PPMI analogues as an innovative platform for accurate H(+) detection. The self-assembly of block copolymers on the nanometer length scale was particularly highlighted as a novel prospective means of regulating fluorescence properties while avoiding the self-quenching phenomenon, and this system can be used as a fast responsive pH sensor in versatile device forms.

Wiring of glucose oxidase (GOx) onto electrode surface was successfully achieved by cross-linked networks of organometallic block copolymers comprising electroactive ferrocene moieties and chemically cross-linkable diene groups, poly(ferrocenyldimethylsilaneb-isoprene)s (PFS−PIs). Different nanoscale morphologies of PFS−PIs, i.e., bicontinuous structure, nanowires, and nanoparticles, have been derived by varying molecular weights and casting solvents. Upon examining catalytic current responses of the GOx integrated PFS−PI systems, notably, the morphology of PFS−PI is found out to be a crucial parameter in determining the efficiency of electron transfer. For example, the use of bicontinuous PFS−PI confirms 2−50 times improved catalytic current densities, compared with the values of other morphologies; the maximum catalytic current of glucose oxidation was 0.7 mA/cm 2 at 70 mM glucose concentration. The biosensing ability of the fabricated electrode with structural optimization was also exploited, and good sensitivity is obtained at the physiological concentration of glucose in blood.