High-Sodium-Concentration Sodium Oxythioborosilicate Glass Synthesized via Ambient Pressure Method with Sodium Polysulfides.

The practical utilization of all-solid-state sodium batteries necessitates the development of a mass synthesis process for high-alkali-content sulfide glass electrolytes, which are characterized by both high ionic conductivity and remarkable formability. Typically, vacuum sealing and quenching are conventional techniques employed during the manufacturing process. In this paper, we present a novel approach, a pioneering method for the production of sulfide glass electrolytes with high alkali concentrations, achieved through ambient-pressure heat treatment and a gradual cooling process. We enhance the glass-forming ability of Na3BS3 by incorporating a small quantity of SiO2. The ionic conductivity of the resulting Na3BS3·0.225SiO2 (molar ratio) glass exhibited 1.5 × 10-5 S cm-1 at 25 °C, surpassing that of Na3BS3 glass. An all-solid-state cell utilizing Na3BS3·0.225SiO2 glass is successfully operated as a secondary battery at 60 °C. Our findings suggest that sodium oxythioborosilicate glass with electrochemical properties identical to those of Na3BS3 can be prepared without the need for quenching. These results propel the advancement of research in the domain of mass production processes tailored for high-alkali-content sulfide glass.

Stabilizing High-Temperature α-Li3PS4 by Rapidly Heating the Glass.

High-temperature metastable phases exhibit superior characteristics compared to those of thermodynamically stable phases at room temperature. Although optimization of the compositions and crystallizations from glasses contribute to the stabilization of metastable phases at room temperature, the stabilization of the high-temperature α-Li3PS4 phase is not yet reported. α-Li3PS4 was successfully stabilized at room temperature, instead of the middle-temperature ß-Li3PS4 phase, via rapid heating to crystallize the Li3PS4 glass. The obtained electrolyte exhibited a high ionic conductivity of >10-3 S cm-1 at room temperature. The crystallization of the glass via rapid heating overcame the thermodynamic limitations in the preparation of the metastable crystals. Further development of materials via nonequilibrium states should contribute to the design of high-performance materials.

High Capacity Li2 S-Li2 O-LiI Positive Electrodes with Nanoscale Ion-Conduction Pathways for All-Solid-State Li/S Batteries.

All-solid-state lithium-sulfur (Li/S) batteries are promising next-generation energy-storage devices owing to their high capacities and long cycle lives. The Li2 S active material used in the positive electrode has a high theoretical capacity; consequently, nanocomposites composed of Li2 S, solid electrolytes, and conductive carbon can be used to fabricate high-energy-density batteries. Moreover, the active material should be constructed with both micro- and nanoscale ion-conduction pathways to ensure high power. Herein, a Li2 S-Li2 O-LiI positive electrode is developed in which the active material is dispersed in an amorphous matrix. Li2 S-Li2 O-LiI exhibits high charge-discharge capacities and a high specific capacity of 998 mAh g-1 at a 2 C rate and 25 °C. X-ray photoelectron spectroscopy, X-ray diffractometry, and transmission electron microscopy observation suggest that Li2 O-LiI provides nanoscale ion-conduction pathways during cycling that activate Li2 S and deliver large capacities; it also exhibits an appropriate onset oxidation voltage for high capacity. Furthermore, a cell with a high areal capacity of 10.6 mAh cm-2 is demonstrated to successfully operate at 25 °C using a Li2 S-Li2 O-LiI positive electrode. This study represents a major step toward the commercialization of all-solid-state Li/S batteries.

Mechanochemical Synthesis and Structure of the Alkali Metal Magnesium Chalcogenide Na6MgS4.

The new binary sodium magnesium sulfide was prepared by the mechanochemical synthesis route from Na2S and MgS as starting materials. Na6MgS4 is extremely sensitive and partially decomposes in the presence of oxygen traces. With the use of an excess of MgS in the milling process, the molar ratio of the impurities was successfully decreased from 38% (Na2S + MgO) to 13% MgO. The crystal structure and properties were characterized by X-ray powder diffraction, thermogravimetry/differential thermal analysis, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and electrochemical impedance spectroscopy. The Rietveld refinement confirmed that Na6MgS4 is isostructural to Na6ZnO4. The compound crystallized in the hexagonal system in the non-centro-symmetric space group P63mc (No. 186) with a = 9.0265(1), c = 6.9524(1) Å, V = 490.58(1) Å3, and Z = 2. The structure consisted of a wurtzite-like 3D framework built up of corner-sharing MgS4 and NaS4 tetrahedra, with 3/4 of the tunnels, parallel to the c axis, filled with octahedrally coordinated sodium atoms. The ionic conductivity of the composite material (87% Na6MgS4 + 13% MgO) being low (4.4 × 10-8 S cm-1 with Ea = 0.56 eV), indium-doped samples Na6-x□xMg1-xInxS4 (x = 0.05, 0.1) were prepared by the mechanochemical synthesis route. These samples also contained 13% MgO. Their ionic conductivities of 9.3 × 10-8 S cm-1 (Ea = 0.51 eV) and 2.5 × 10-7 S cm-1 (Ea = 0.49 eV) at 25 °C for x = 0.05 and 0.1, respectively, were higher than the ionic conductivity of the undoped sample.

Iron Sulfide Na2 FeS2 as Positive Electrode Material with High Capacity and Reversibility Derived from Anion-Cation Redox in All-Solid-State Sodium Batteries.

It is desirable for secondary batteries to have high capacities and long lifetimes. This paper reports the use of Na2 FeS2 with a specific structure consisting of edge-shared and chained FeS4 as the host structure and as a high-capacity active electrode material. An all-solid-state sodium cell that uses Na2 FeS2 exhibits a high capacity of 320 mAh g-1 , which is close to the theoretical two-electron reaction capacity of 323 mAh g-1 , and operates reversibly for 300 cycles. The excellent electrochemical properties of all-solid-state sodium cells are derived from the anion-cation redox and rigid host structure during charging/discharging. In addition to the initial one-electron reaction of Nax FeS2 (1 ≤ x ≤ 2) activated Fe2+ /Fe3+ redox as the main redox center, the reversible sulfur redox further contributes to the high capacity. Although the additional sulfur redox affects the irreversible crystallographic changes, stable and reversible redox reactions are observed without capacity fading, owing to the local maintenance of the chained FeS4 in the host structure. Sodium iron sulfide Na2 FeS2 , which combines low-cost elements, is one of the candidates that can meet the high requirements of practical applications.

Changes in depressive symptoms among family caregivers of patients with cancer after bereavement and their association with resilience: A prospective cohort study.

OBJECTIVES: To elucidate changes in depressive symptoms after bereavement and the impact of pre-loss resilience on such changes and on the extent of complicated grief and posttraumatic growth. METHODS: Prospective cohort surveys were provided to family caregivers of patients with cancer in four palliative care units (PCUs) before and after bereavement. Pre-loss Connor-Davidson Resilience Scale scores, pre- and post-loss Patient Health Questionnaire-9 scores, post-loss Brief Grief Questionnaire scores, and the expanded Posttraumatic Growth Inventory scores were determined. RESULTS: Out of 186 bereaved family caregivers, 71 (38.2%) responses were analyzed, among which 47% pre-loss and 15% post-loss responses suggested to be a high risk for major depressive disorder (MDD). Approximately 90% of family caregivers at a high risk for post-loss MDD were already at a high risk for pre-loss MDD. Even after adjustment of the background variables as covariates, the interaction effect between family caregivers' pre-loss depressive symptoms and resilience on post-loss depressive symptoms was observed (F = 7.29; p < 0.01). Moreover, pre-loss resilience was not associated with other bereavement outcome measures. CONCLUSIONS: Among family caregivers of patients with cancer in PCUs, 47% and 15% had high risk for MDD before and after bereavement, respectively. Moreover, pre-loss resilience mitigated post-loss depressive symptoms among family caregivers who had high risk for MDD before bereavement. However, considering the study's small sample size, further research is needed.

Reaction uniformity visualized by Raman imaging in the composite electrode layers of all-solid-state lithium batteries.

The reaction uniformity of LiCoO2 composite positive electrodes in all-solid-state cells was compared quantitatively by investigating the Raman band shifts corresponding to the state-of-charge (SOC) of LiCoO2. The quantitative SOC analysis was conducted using the Raman imaging data of composite electrodes with smaller or larger solid electrolytes. The electrodes exhibited different reaction uniformity although the cells showed similar initial charge capacities and average SOC. In the case of larger solid electrolytes, most LiCoO2 particles showed higher or lower SOC than the average SOC, and lower battery performance. The quantitative analysis of SOC in each LiCoO2 electrode demonstrated that a variable SOC outside the average SOC resulted in larger irreversible capacity and lower rate performance. The quantitative SOC analysis newly developed in the present study is a useful technique for designing composite electrodes showing higher battery performance.

Mechanochemical Synthesis and Characterization of Metastable Hexagonal Li4SnS4 Solid Electrolyte.

A new crystalline lithium-ion conducting material, Li4SnS4 with an ortho-composition, was prepared by a mechanochemical technique and subsequent heat treatment. Synchrotron X-ray powder diffraction was used to analyze the crystal structure, revealing a space group of P63/ mmc and cell parameters of a = 4.01254(4) Å and c = 6.39076(8) Å. Analysis of a heat-treated hexagonal Li4SnS4 sample revealed that both lithium and tin occupied either of two adjacent tetrahedral sites, resulting in fractional occupation of the tetrahedral site (Li, 0.375; Sn, 0.125). The heat-treated hexagonal Li4SnS4 had an ionic conductivity of 1.1 × 10-4 S cm-1 at room temperature and a conduction activation energy of 32 kJ mol-1. Moreover, the heat-treated Li4SnS4 exhibited a higher chemical stability in air than the Li3PS4 glass-ceramic.

Effects of Lithium Halides on Electrode-Electrolyte Bifunctional Materials for High-Capacity All-Solid-State Batteries.

All-solid-state batteries have attracted attention because of their high energy density, safety, and long cycle life. Sulfide active materials exhibit high capacities and enable an enhanced energy density in all-solid-state batteries. In this study, we synthesized electrode-electrolyte bifunctional materials in the system Li2S-V2S3-LiX (X = F, Cl, Br, or I) through a mechanochemical process. In addition, the effects of the addition of lithium halides on the electrochemical properties were investigated. All-solid-state batteries with the Li2S-V2S3-LiI electrode showed the highest capacity of 400 mAh g-1 among all the cells, even though their electronic and ionic conductivities were the same. From the point of view of the ionic conductivity and structure of the electrodes during cycling, it was clarified that a high reversible capacity was achieved not only by high ionic and electronic conductivities before cycling but also by maintaining the ionic conductivity even at the deep state of charge. Furthermore, high-loading all-solid-state cells were fabricated using the Li2S-V2S3-LiI materials with a mass loading of 37.3 mg cm-2, exhibiting a high areal capacity of approximately 11.5 mAh cm-2 at 60 °C and good cycle performance.

Mechanochemical synthesis of fluoride-ion conducting glass and glass-ceramic in ZrF4-BaF2 binary system.

Fluoride glasses in the binary system ZrF4-BaF2 were prepared via mechanochemical treatment. The glass-forming region of the ZrF4-BaF2 system obtained using the mechanochemical method was wider than that obtained using the conventional melt-quenching method. The glass-ceramic 60ZrF4·40BaF2 (mol%) sample was obtained by heat treatment and shows a higher conductivity of 1.2 × 10-6 S cm-1 at 200 °C than the pristine glass. This study revealed that mechanochemical treatment was effective for the synthesis of fluoride glasses.

In situ SEM study of a lithium deposition and dissolution mechanism in a bulk-type solid-state cell with a Li2S-P2S5 solid electrolyte.

In situ SEM observation of a lithium deposition and dissolution process in an all-solid-state lithium metal battery using a sulfide-based solid electrolyte (SE) was carried out. We revealed visually that the morphology of lithium deposition varies with the operating current densities. At current densities higher than 1 mA cm(-2), local lithium deposition triggers large cracks, leading to a decrease in the reversibility of lithium deposition and dissolution. On the other hand, at a low current density of 0.01 mA cm(-2), its homogeneous deposition, which enables the reversible deposition and dissolution, hardly brings about the occurrence of unfavorable cracks. These results suggest that homogeneous lithium deposition on the SE and the suppression of the growth of lithium metal along the grain boundaries inside the SE are keys to achieve the repetitive lithium deposition and dissolution reaction without deterioration of the SE.

Stack Pressure Dependence of Li Stripping/Plating Performance in All-Solid-State Li Metal Cells Containing Sulfide Glass Electrolytes.

Sulfide-based all-solid-state Li/S batteries have attracted considerable attention as next-generation batteries with high energy density. However, their practical applications are limited by short-circuiting due to Li dendrite growth. One of the possible reasons for this phenomenon is the contact failure caused by void formation at the Li/solid electrolyte interface during Li stripping. Herein, we studied the operating conditions, such as stack pressure, operating temperature, and electrode composition, that could potentially suppress the formation of voids. Furthermore, we investigated the effects of these operating conditions on the Li stripping/plating performance of all-solid-state Li symmetric cells containing glass sulfide electrolytes with a reduction tolerance. As a result, symmetric cells with Li-Mg alloy electrodes instead of Li metal electrodes exhibited high cycling stability at current densities above 2.0 mA cm-2, a temperature of 60 °C, and stack pressures of 3-10 MPa. In addition, an all-solid-state Li/S cell with a Li-Mg alloy negative electrode operated stably for 50 cycles at a current density of 2.0 mA cm-2, stack pressure of 5 MPa, and temperature of 60 °C, while its measured capacity was close to a theoretical value. The obtained results provide guidelines for the construction of all-solid-state Li/S batteries that can reversibly operate at high current densities.

Unique Li deposition behavior in Li3PS4 solid electrolyte observed via operando X-ray computed tomography.

The problem of lithium dendrites must be addressed for practical lithium metal all-solid-state batteries. Herein, three-dimensional morphological changes within Li3PS4 electrolyte away from the anode were observed using operando X-ray computed tomography. We revealed that the electronic conduction of decomposition and the electrolyte/void interface cause the lithium deposition within the Li3PS4.

Characteristics of caregiver perceptions of end-of-life caregiving experiences in cancer survivorship: in-depth interview study.

OBJECTIVE: Little is known about caregiver experiences during the end-of-life period. Our objective was to characterize caregiver perceptions of their experiences in cancer survivorship with special reference to the end-of-life stage considering depression in bereavement. METHODS: Qualitative research using in-depth interviews of 34 caregivers from two palliative care units in Japan. Data were analyzed inductively using framework analysis. Depression and personality traits were measured using the Center for Epidemiological Studies Depression (CES-D) and Sense of Coherence (SOC) scales, respectively. RESULTS: Caregiver perceptions were characterized along two axes. One axis involved four caregiver-cancer patient relationships: strengthening, reconstruction, intimacy-maintained, and estrangement-maintained. The core concept was transformation of relationships: caregivers reappraised aspects of caregiver-patient interactions through caregiving. The other axis involved subjective caregiving experiences divided into five concepts: spontaneity of care, discussing death, sympathy for patient emotions, impressions on first witnessing death, and introspective reflections in bereavement. Strengthening and reconstruction relationships appeared similar among the four relationship types, but only the former tended to overcompensate by sacrificing private time. Although median CES-D scores in each relationship type were under the cutoff for possible depression, four of eight caregivers suspected to have depressive tendencies belonged to the strengthening type. The mean SOC score for all caregivers was intermediate relative to scores previously reported in Japanese studies. CONCLUSIONS: While caregivers' subjective experiences can be classified, their relationship to depression in bereavement needs future research. The present findings indicate that caregivers should also be considered in clinicians' views of cancer survivorship.

Cost-saving prediction model of transfer to palliative care for terminal cancer patients in a Japanese general hospital.

Background: Although medical costs need to be controlled, there are no easily applicable cost prediction models of transfer to palliative care (PC) for terminal cancer patients. Objective: Construct a cost-saving prediction model based on terminal cancer patients' data at hospital admission. Study design: Retrospective cohort study. Setting: A Japanese general hospital. Patients: A total of 139 stage IV cancer patients transferred to PC, who died during hospitalization from April 2014 to March 2019. Main outcome measure: Patients were divided into higher (59) and lower (80) total medical costs per day after transfer to PC. We compared demographics, cancer type, medical history, and laboratory results between the groups. Stepwise logistic regression analysis was used for model development and area under the curve (AUC) calculation. Results: A cost-saving prediction model (AUC = 0.78, 95% CI: 0.70, 0.85) with a total score of 13 points was constructed as follows: 2 points each for age ≤ 74 years, creatinine ≥ 0.68 mg/dL, and lactate dehydrogenase ≤ 188 IU/L; 3 points for hemoglobin ≤ 8.8 g/dL; and 4 points for potassium ≤ 3.3 mEq/L. Conclusion: Our model contains five predictors easily available in clinical settings and exhibited good predictive ability.

Formation of Passivate Interphases by Na3BS3-Glass Solid Electrolytes in All-Solid-State Sodium-Metal Batteries.

Interphase formation at the interface between a solid electrolyte and negative electrode is one of the main factors limiting the practical use of all-solid-state sodium batteries. Sulfide-type solid electrolytes with group 15 elements (P and Sb) exhibit high ductility and ionic conductivity, comparable to those of organic liquid electrolytes. However, the electronically conductive interphase formed at the interface between Na3PS4 and sodium metal increases the cell resistance and deteriorates its electrochemical properties. Contrarily, Na3BS3, containing boron as an electrochemically inert element, forms an electronically insulating thin passivate interphase, facilitating reversible sodium plating and stripping. Sodium-metal symmetric cells with Na3BS3 exhibit steady operation over 1000 cycles. Thus, reduction-stable solid electrolytes can be developed by substitution with an electrochemically inert element versus sodium.

Phase-selective synthesis of nickel phosphide in high-boiling solvent for all-solid-state lithium secondary batteries.

Nickel phosphide particles were synthesized by thermal decomposition of a nickel precursor in a mixed solution of trioctylphosphine and trioctylphosphine oxide. The crystal phase and morphology of samples prepared by changing the solvents, the amount of trioctylphosphine as a phosphorus source, the reaction temperature, and the nickel precursor were characterized using X-ray diffraction and transmission electron microscopy. Spherical Ni(5)P(4) particles with diameters of 500 nm were obtained using nickel acetylacetonate as a nickel precursor at 360 °C for 1 h in trioctylphosphine oxide. NiP(2) particles with diameters of 200-500 nm were obtained using nickel acetate tetrahydrate at 360 °C for 5 h in trioctylphosphine oxide. All-solid-state cells were fabricated using NiP(2) particles as an active material and 80Li(2)S·20P(2)S(5) (mol %) glass-ceramic as a solid electrolyte. The Li-In/80Li(2)S·20P(2)S(5)/NiP(2) cell exhibited an initial discharge capacity of 1100 mAh g(-1) at a current density of 0.13 mA cm(-2) and retained a discharge capacity of 750 mAh g(-1) after 10 cycles.

A 2-week prognostic prediction model for terminal cancer patients in a palliative care unit at a Japanese general hospital.

OBJECTIVE: We aimed to develop a prognostic prediction model for 2-week survival among patients with terminal cancer in a palliative care unit (PCU). METHODS: A prospective cohort study was conducted on terminal cancer patients in the PCU for 11 months at a general hospital in Tokyo, Japan. We collected data regarding demographics, treatment history, performance status, symptoms, and laboratory results. Patients who survived more than 2 weeks were labeled 'long survivors' and those who died within 2 weeks were grouped as 'short survivors'. Stepwise logistic regression model was constructed for the model development and bootstrapping was used for the internal model validation. RESULTS: In 158 subjects whose data were available for the analysis, 109 (69%) subjects were categorized as long survivors and 49 (31%) subjects as short survivors. A prognostic prediction model with a total score of 8 points was constructed as follows: 2 points each for anorexia, dyspnea, and edema; 1 point each for blood urea nitrogen >25 mg/dl and platelets <260,000/mm(3). Area under the receiver operating characteristic (ROC) curve of this model was 83.2% (95% CI: 75.3-91.0%). Bootstrapped validation beta coefficients of the predictors were similar to the original cohort beta coefficients. CONCLUSION: Our prognostic prediction model for estimating 14-day survival for patients with terminal cancer on the PCU ward included five clinical predictors that are readily available in the clinical setting and showed a relatively high accuracy. External validation is needed to confirm the model's generalizability.

Real-World Cost-Effectiveness of Palliative Care for Terminal Cancer Patients in a Japanese General Hospital.

Background: The concept of cost-effectiveness is necessary for optimal utilization of limited health care resources. However, few studies have assessed the cost-effectiveness of palliative care using quality-adjusted life years (QALYs), considered common outcomes in health economics. Objective: We aimed to perform a cost-effectiveness analysis of palliative care for terminal cancer patients by using QALYs. Design: A retrospective cohort study was performed. Setting/Patients: We included 401 patients with stage IV cancer, who were hospitalized and died at a Japanese general hospital during the period April 2014 to March 2019. Methods: Using the hospital database, we compared the total admission costs and QALYs based on pain levels of patients admitted to the palliative care (PC) department with those of patients admitted to other usual care (UC) departments. Patients in each group were matched through propensity scores to reduce bias. Bootstrapping estimated the 95% confidence intervals (95% CIs) and the probability that PC was more cost-effective than UC. Results: After matching, 128 patients in each group were selected. Converting 1 U.S. dollar (USD) to 100 Japanese yen, PC reduced mean total admission costs by 1732 USD (95% CI: 1584-1879) and improved mean health benefits by 0.0028 QALYs (95% CI: 0.0025-0.0032) compared with UC. Based on the Japanese cost-effectiveness threshold, there was an 82% probability that PC was more cost-effective than UC. Conclusions: Our results indicated that admission of terminal cancer patients to the PC department was associated with improvement in cost-effectiveness. This finding could support the introduction of palliative care for terminal cancer patients. Our study was approved at St. Luke's International University (receipt number 18-R061 and at the Graduate School of Pharmaceutical Sciences, The Univesity of Tokyo (receipt number 31-29).

Structures and conductivities of stable and metastable Li5GaS4 solid electrolytes.

Understanding the differences in the structures and defects in the stable crystalline phase and metastable phase is important for increasing the ionic conductivities of a solid electrolyte. The metastable phase often has higher conductivity than the stable phase. In this study, metastable lithium thiogallate, Li5GaS4, was synthesized via mechanochemistry and stable Li5GaS4 was obtained by heating the metastable phase. The metastable Li5GaS4 sample was found to have an antifluorite-type crystal structure with cationic disorder, while the stable phase was found to have a monoclinic crystal structure, similar to that of another solid electrolyte, Li5AlS4. In both the structures, the Ga3+ cations were surrounded by four S2- anions in tetrahedral coordination. The conductivity of the metastable phase was determined to be 2.1 × 10-5 S cm-1 at 25 °C, which is 1000 times greater than that of the monoclinic phase. The high conductivity of the metastable phase was achieved owing to cation disorder in the crystal structure.