MONOLITHICALLY INTEGRATED, PRINTED SOLID-STATE RECHARGEABLE BATTERIES WITH AESTHETIC VERSATILITY

Department of Energy Engineering (Battery Science and Technology)With the advent of flexible/wearable electronics and Internet of Things (IoT) which are expected to drastically change our daily lives, printed electronics has drawn much attention as a low cost, efficient, and scalable platform technology. The printed electronics requires so-called “printed batteries” as a monolithically integrated power source that can be prepared by the same printing processes. The printing technology is a facile and reproducible process in which slurries or inks are deposited to make pre-defined patterns. The slurries/inks should be designed to fulfill requirements (such as rheology and particle dispersion) of the printing process. Development of printed batteries involves the design and fabrication of battery component slurries/inks. Most studies of the printed batteries have been devoted to the development of printed electrodes. However, in order to reach an ultimate goal of so-called “all-printed-batteries”, printed separator membranes and printed electrolytes should be also developed along with the printed electrodes. The objective of the research presented in this dissertation is to develop materials and printing-based strategies to fabricate a new class of monolithically integrated, printed solid-state rechargeable batteries with aesthetic versatility to address the aforementioned formidable challenges, with particular attention to comprehensive understanding of colloidal microstructure and rheological/electrochemical properties of printable battery component slurries/inks. Colloidal microstructure of the battery component slurries/inks is expected to play a viable role in realizing the monolithically integrated printed batteries, as it can significantly affect fluidic characteristics of the slurries/inks and also electrochemical properties. In particular, our interest is devoted to concentrated colloidal gels that exhibit thixotropic fluid behavior (i.e., they readily flow upon being subjected to external stress and quickly return to a quiescent state). Driven by such unique viscoelastic response, the slurries/inks show good dimensional stability and shape diversity on various objects. In addition to the viscoelasticity control of the slurries/inks, the interaction between colloidal conductive particles should be carefully tuned in order to secure facile ion and electron transport pathways. When the attractive interaction is dominant, the colloidal particles tend to be aggregated in disordered and dynamically arrested forms, yielding the highly reticulated three-dimensional networks. In an electrochemical system, these interconnected conductive particle networks act as electron conduction channels while the interstitial voids formed between the particle networks allows ion transport. In this dissertation, as a proof-of-concept, lithium-ion batteries (LIBs), electric double layer capacitors (EDLCs), and Zn-air batteries are chosen to explore the feasibility of this approach. The resultant solid-state printed batteries are fabricated through various printing processes such as stencil printing, inkjet printing, and pen-based writing. Notably, the printed batteries can be seamlessly integrated with objects or electronic devices, thus offering unprecedented opportunities in battery design and form factors that lie far beyond those achievable with conventional battery technologies.ope

A MODEL ON AN ENTRAINED BED-BUBBLING BED PROCESS FOR CO2 CAPTURE FROM FLUE GAS

A simplified model has been developed to investigate effects of important operating parameters on performance of an entrained-bed absorber and bubbling-bed regenerator system collecting CO2 from flue gas. The particle population balance was considered together with chemical reaction to determine the extent of conversion in both absorber and regenerator. Effects of several absorber parameters was tested in a laboratory scale process. The CO2 capture efficiency decreased as temperature or gas velocity increased. However, it increased with static bed height or moisture concentration. The CO2 capture efficiency was exponentially proportional to each parameter. Based on the absolute value of exponent of the parameter, the effect of gas velocity, static bed height, and moisture content was a half, one third, and one fourth as strong as that of temperature, respectively

Gelatin-layered and multi-sized porous β-tricalcium phosphate for tissue engineering scaffold

The multi-sized porous β-tricalcium phosphate scaffolds were fabricated by freeze drying followed by slurry coating using a multi-sized porous sponge as a template. Then, gelatin was dip coated on the multi-sized porous β-tricalcium phosphate scaffolds under vacuum. The mechanical and biological properties of the fabricated scaffolds were evaluated and compared to the uniformly sized porous scaffolds and scaffolds that were not coated by gelatin. The compressive strength was tested by a universal testing machine, and the cell viability and differentiation behavior were measured using a cell counting kit and alkaline phosphatase activity using the MC3T3-E1 cells. In comparison, the gelatin-coated multi-sized porous β-tricalcium phosphate scaffold showed enhanced compressive strength. After 14 days, the multi-sized pores were shown to affect cell differentiation, and gelatin coatings were shown to affect the cell viability and differentiation. The results of this study demonstrated that the multi-sized porous β-tricalcium phosphate scaffold coated by gelatin enhanced the mechanical and biological strengths

Measurement of Blood Pressure Using an Arterial Pulsimeter Equipped with a Hall Device

To measure precise blood pressure (BP) and pulse rate without using a cuff, we have developed an arterial pulsimeter consisting of a small, portable apparatus incorporating a Hall device. Regression analysis of the pulse wave measured during testing of the arterial pulsimeter was conducted using two equations of the BP algorithm. The estimated values of BP obtained by the cuffless arterial pulsimeter over 5 s were compared with values obtained using electronic or liquid mercury BP meters. The standard deviation between the estimated values and the measured values for systolic and diastolic BP were 8.3 and 4.9, respectively, which are close to the range of values of the BP International Standard. Detailed analysis of the pulse wave measured by the cuffless radial artery pulsimeter by detecting changes in the magnetic field can be used to develop a new diagnostic algorithm for BP, which can be applied to new medical apparatus such as the radial artery pulsimeter

Femoral Neuropathy due to Iliacus Muscle Hematoma in a Patient on Warfarin Therapy

Spontaneous hematomas of the iliacus muscle are rare lesions and these are seen in individuals receiving anticoagulation therapy or patients with blood dyscrasias such as hemophilia. It can cause femoral neuropathy and resultant pain and paralysis. Although there is no clear consensus for the treatment of femoral neuropathy from iliacus muscle hematomas, delays in the surgical evacuation of hematoma for decompression of the femoral nerve can lead to a prolonged or permanent disability. We report here on a rare case of a spontaneous iliacus muscle hematoma that caused femoral neuropathy in a patient who was taking warfarin for occlusive vascular disease and we discuss the treatment

Analysis of Long-Range Transport of Carbon Dioxide and Its High Concentration Events over East Asian Region Using GOSAT Data and GEOS-Chem Modeling

This study aims to evaluate the long-range transport of CO2 in East Asian region, using concentration data in a surface measurement site (Gosan Station), column averaged concentration data of satellite-borne instrument (GOSAT), and GEOS-Chem modeling results for the period of June 2009 to May 2011. We perform a validation of the data from GOSAT and GEOS-Chem with total column observations (TCCON). The analysis of the long-range transport and high concentration (HC) events using surface/satellite observations and modeling results is conducted. During the HC events, the concentrations in CO2 and other air pollutants such as SO2 and CO are higher than that of all episodes. It means that CO2, known as a globally well-mixed gas, may also act as a fingerprint of human activity with unique regional characteristics like other air pollutants. This comprehensive analysis, in particular with GOSAT CO2 observation data, shows that CO2 plume with high concentration can be long-range transported with 1-2 days' duration with regional scale. We can find out with GEOS-Chem tagging simulation that more than 45% of the elevated CO2 concentration over central/eastern China, Korea, and Japan on high concentration days can be explained by emission sources of East Asia mainland.open0