10 research outputs found
Zirconium trisulfide as a promising cathode material for Li primary thermal batteries
In this work ZrS3 has been synthesized by solid state reaction in a sealed quartz tube and investigated as a candidate cathode material in Li thermal batteries. The structure of ZrS3 before and after cell testing has been studied using powder X-ray diffraction. A new spinel related material, LiZr2S4, has been identified as the product of the electrochemical process, which can be indexed to a = 10.452(8) Å cubic unit cell. The electrochemical properties of the batteries were investigated at 500 °C against Li13Si4 by galvanostatic discharge and galvanostatic intermittent titration technique (GITT). In a thermal Li cell at 500 °C a single voltage plateau of 1.70 V at a current density of 11 mA/cm2 was achieved with capacity of 357 mA h g-1. Therefore ZrS3 material has some promise as a cathode for Li thermal batteries.Publisher PDFPeer reviewe
Transition metal chlorides NiCl2, KNiCl3, Li6VCl8 and Li2MnCl4 as alternative cathode materials in primary Li thermal batteries
Special thanks to AWE Plc for their support and funding for this work. The authors would also like to acknowledge the EPSRC Platform Grant EP/K015540/1 and the Royal Society Wolfson Merit Award WRMA 2012/R2.Transition metal chlorides KNiCl3, Li6VCl8 and Li2MnCl4 were synthesized by solid state reaction in sealed quartz tubes and investigated as candidate cathode materials along with NiCl2 in Li thermal batteries. The structure and morphology were studied and electrochemical properties probed at high temperatures (400°C–500°C) against Li13Si4 by galvanostatic discharge and galvanostatic intermittent titration technique (GITT). All the transition metal chlorides reduced to metal and the products of the discharge mechanism were confirmed by powder X-ray diffraction. NiCl2 was tested at 500°C and a capacity of 360 mAhg−1 was achieved. KNiCl3 was tested at different current densities from 15 mA/cm2 to 75 mA/cm2 and a high voltage profile 2.30V was achieved at 425°C with a capacity of 262 mAhg−1. Li6VCl8 was tested at 500°C and a 1.80V voltage plateau at a current density of 7.5 mA/cm2 was achieved with a capacity of 145 mAhg−1. Li2MnCl4 was tested at the same current density at 400°C and a capacity of 254 mAhg−1 was achieved. These transition metal chlorides exhibit higher voltage against Li13Si4 and, hence, provide more specific power compared to the well-known metal disulfides MS2 (M = Fe, Co, Ni) and may be promising cathode materials for Li thermal batteries.Publisher PDFPeer reviewe
In-situ studies of high temperature thermal batteries : a perspective
Funding: UK Engineering and Physical Sciences Research Council (EP/P007821/1).Here we present a perspective on in-situ studies of high temperature batteries. We focus on a primary battery technology- the thermal battery- which possesses a molten salt electrolyte. We discuss aspects of sample environment design, data collection and will briefly look at some case studies. We aim to highlight the importance of using in-situ techniques in studying electrochemical devices such as high temperature batteries.Publisher PDFPeer reviewe
Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries
Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely
Development of the Ca/FeS<sub>2</sub> chemistry for thermal batteries
Alternative battery chemistries are the focus of growing attention due to their potential advantages over lithium; however, the field of thermal batteries sees much less research into alternative chemistries, as the current lithium alloy–metal sulfide cell is seen as the “gold standard”. In this work, we demonstrate the operation of a thermal battery using a calcium-containing eutectic and calcium metal against the FeS2 cathode material. An initial assessment of the CaCl2–NaCl eutectic is presented, showing that it is a good candidate for use as an electrolyte. Cells were assembled and characterized using a range of physical and electrochemical techniques, and their properties were studied. Discharge voltages at low current densities were promising, with cells displaying discharge voltages >2 V and capacities in excess of 100 mAh g–1. Rate capability was also explored, which can be improved by modification of the cathode. Although the cathode material was not fully utilized during discharge, there was evidence of electrochemical reactions occurring, which were explored in detail using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and neutron diffraction. It is hoped that these results will stimulate development and ideas for high-temperature battery chemistries, expanding the horizons of these types of batteries for new applications
Development of the Ca/FeS<sub>2</sub> chemistry for thermal batteries
Alternative battery chemistries are the focus of growing attention due to their potential advantages over lithium; however, the field of thermal batteries sees much less research into alternative chemistries, as the current lithium alloy–metal sulfide cell is seen as the “gold standard”. In this work, we demonstrate the operation of a thermal battery using a calcium-containing eutectic and calcium metal against the FeS2 cathode material. An initial assessment of the CaCl2–NaCl eutectic is presented, showing that it is a good candidate for use as an electrolyte. Cells were assembled and characterized using a range of physical and electrochemical techniques, and their properties were studied. Discharge voltages at low current densities were promising, with cells displaying discharge voltages >2 V and capacities in excess of 100 mAh g–1. Rate capability was also explored, which can be improved by modification of the cathode. Although the cathode material was not fully utilized during discharge, there was evidence of electrochemical reactions occurring, which were explored in detail using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and neutron diffraction. It is hoped that these results will stimulate development and ideas for high-temperature battery chemistries, expanding the horizons of these types of batteries for new applications