ABSTRACT
Solid-state lithium-metal batteries (SSLMBs) have attracted great attention due to their outstanding advantages in safety, electrochemical stability and interfacial compatibility. However, the low ionic conductivity and narrow electrochemical window restrict their practical application. Herein, in-situ polymerization electrolytes (IPEs) crosslinked by acrylonitrile (AN) and ethylene glycol dimethacrylate (EGDMA) exhibit the superior ionic conductivity of 1.77×10-3â S cm-1 at 25 °C, the ultrahigh lithium transference number (tLi+) of 0.784 and the wider electrochemical stable window (ESW) of 5.65â V. The IPEs make the symmetrical Li||Li cells achieve the highly stable lithium stripping/plating cycling for over 3000â h at 0.1â mA cm-2. Meanwhile, IPE endows the solid-state LiFePO4||Li batteries with an excellent long-cycle performance over 700 cycles at 2.5â C with a capacity retention ratio over 95 %, as well as 1000 cycles at 1â C and superior capacity retention of 85 %. More importantly, the in-situ polymerized electrolytes containing polyacrylonitrile (PAN) open up a new frontier to promote the practical application of solid-state batteries with high safety and high energy density via in-situ solidification technology.
ABSTRACT
Background: Compared with urban areas, old adults in rural areas have limited access to medical and health resources in China. Active of daily living ability (ADL) decline and depressive symptoms are common in rural older adults. In particular, the depressive symptoms of the elderly in rural areas are often ignored. Thus, it is difficult to realize high-level active aging at the individual level. In order to explore the effects of ADL and depressive symptoms on the active aging of rural elderly, we conducted a survey and analyzed the mediation and interaction effects of depressive symptoms of ADL on active aging. Methods: From July to November 2019, a cross-sectional study of 945 elderly rural individuals was conducted in three townships in Xiangtan County, China. Active aging, ADL, and depressive symptoms were assessed using the positive aging questionnaire (PAEQ), ADL scale, and depression in old age scale (DIA-S), respectively. PROCESS macro program model 4 and logistic regression were used to explore the mediation and interaction between ADL and depressive symptoms on active aging. Results: The proportions of rural elderly with an active aging level were 23.5% (well above average), 50.9% (above average), 24.1% (below average), 1.5% (well below average), respectively. The rates of ADL decline and depressive symptoms were 44.7 and 19.7%, respectively. Mediated effect analysis showed that the relationship between ADL and active aging could be partly mediated by depressive symptoms (ab = -0.2382, boot SE = 0.0437), and the 95% confidence interval was [-0.3311, -0.1584]. The mediating effect proportion of the total effect was 30.7%. Logistic regression showed that ADL and depressive symptoms have an interactive additive effect on active aging. The relative excess risk of interaction (RERI), the attributable proportion due to interaction (API), and the synergy index (SI) scores were 13.109, 0.621, and 2.871, respectively. Older adults with ADL decline and depressive symptoms had higher (OR = 21.115) odds of well-below-average active aging compared with older adults with ADL decline (OR = 3.258) or only depressive symptoms (OR = 5.749). Conclusion: The findings suggest that the association between ADL and active aging is persistent and partly mediated by depressive symptoms, and comorbid depressive symptoms and ADL decline have an additive effect on active aging. Maintaining independence is an important factor for realizing active aging. However, for the rural elderly with ADL decline and low-level active aging, we can promote the realization of high-level active aging at the individual level through the prevention and treatment of depressive symptoms based on multidisciplinary care.