Dawei Zhang

Lithium/sulfur cells have attracted much attention due to their higher theoretical specific capacity and energy compared to those of current lithium-ion cells. However, the application of Li/S cells is still hampered by short cycle life. Sulfur-graphene oxide nanocomposites have shown promise as cathode materials for long-life Li/S cells because oxygen-containing functional groups on the surface of graphene oxide were successfully used as sulfur immobilizers by forming weak bonds with sulfur and polysulfides. While S-GO showed much improved cycling performance, the capacity decay still needs to be improved for commercially viable cells. In this study, we attempt to understand the capacity fading mechanism based on an ex situ study of the structural and chemical evolution of S-GO nanocomposite cathodes with various numbers of cycles using scanning electron microscopy, near edge X-ray absorption fine structure and X-ray photoelectron spectroscopy. It is found that both the surface morphologies and chemical structures of the cathode materials change considerably with increasing number of cycles. These changes are attributed to several unexpected chemical reactions of lithium with S-GO nanocomposites occurring during the discharge-charge processes with the formation of Li2CO3, Li2SO3, Li 2SO4, and COSO2Li species. These reactions result in the loss of recyclable active sulfur on the surface of the electrode, and thus capacity fades while coulombic efficiency is near 100%. Moreover, the reaction products accumulate on the cathode surface, forming a compact blocking insulating layer which may make the diffusion of Li ions into/out of the cathode difficult during the discharge-charge process and thus lead to lower utilization of sulfur at higher rates. We think that these two observations are significant contributors to the capacity and rate capability degradation of the Li/S-GO cells. Therefore, for the rechargeable Li/S-GO cells, we suggest that the content of oxygen-containing functional groups on GO should be optimized and more stable functional groups need to be identified for further improvement of the cycling performance. The information we gain from this study may provide general insights into the fundamental understanding of the degradation mechanisms of other rechargeable Li/S cells using similar oxygen-containing functional groups as sulfur immobilizers. © the Partner Organisations 2014.

The research method of Buddhist ethics is contemporary ethical theory, which focuses on precepts (Sila) and disciplines (Vinaya) in experience, rather than transcendental moral ideals (Nirvana or wisdom). Precepts are seen as external norms, while disciplines are internal norms. The former belongs to rule ethics and the latter belongs to virtue ethics. Although the exposition of duty and responsibility can be discovered in Buddhist ethics, there is no sufficient reason to interpret Buddhist ethics as deontology. Views on the consequences of actions can also be found in Buddhist classics, but it is hard to say that Buddhist ethics is the theory of consequences or utilitarianism. The method of rule ethics in the discussion of Buddhist ethics has failed, and Buddhist virtue ethics is a feasible alternative. However, previous research on Buddhist virtue ethics was not perfect, and the teleology of Aristotelian was reasonably criticized. Influenced by caring ethics, emotionalism virtue ethics is a more suitable way to understand Buddhist ethics. The moral reason for Buddhism is a whole argumentation system, including moral rules and moral virtues.

Normal interpersonal treatment is often based on the existence of the rational nature of both the agent and the target of the treatment, and their relationship is reciprocal and mutual. However, when the rational person confronts the irrational person, such as the mentally retarded or vegetative person, the reciprocal relationship cannot be maintained because the targeted person loses his or her rational capacity. But this inequality does not deprive the object of action of the right to be treated rationally, because people treat the irrationally disabled not according to the principle of reason but according to the principle of emotion - specifically, the principle of love. The principle of love often disregards the specific conditions of the object of treatment and still treats them reasonably. Thus, the emotional principle has a broader application in interpersonal treatment.

Intertextuality (mutual illustration) is a common rhetorical device in ancient Chinese and has been used many times in Laozi (Dao Dejing). Intertextuality (mutual illustration) is of unique significance for understanding the linguistic structure and philosophical thoughts of Lao-zi. According to the current research on mutual illustration rhetoric on ancient Chinese, the forms of this rhetoric in Laozi can be divided into mutual illustration of single sentence, of multiple sentences and of ellipsis and antisense. There are only two references to mutual illustration in the annotations of Laozi in the past dynasties, and most of the commentators ignore the importance of mutual illustration in understanding Laozi. By interpreting Laozi through mutual illustration rhetoric, we can make innovations in understanding methods, understanding contents and philosophical thoughts.

From the perspective of perceptual ontology, Laozi criticizes the unnatural state in which the body is concealed in the perceptual social power and ethical relations, and advocates the perceptual liberation of the body. According to different subjects of the body, the covered body should be divided into people’s body and monarchs’ body. The body of the people is concealed in the rites and music, and could be liberated by resuming production; the body of the monarchs is covered in the excessive exercise of power, and could be liberated in the restraint of power. The body is not only in the ethical relationship of the different order pattern, but also in the power relationship of the same structure of family and country. The power, body and ethics form the internal structure of trinity. The perceptual existence of the body is the basis of power and ethics, and the perceptual liberation of the body is the purpose of power and ethics.

In order to have an effective and reliable understanding of the basic moral concepts, moral propositions and moral reasoning in Daoist ethical thoughts, it is necessary to use the methods of doing philosophy and doing ethics to engage in research work, and thus draw an intellectual conclusion about Daoist ethics. The methods of Daoist ethics mainly include analysis, explanation and comparison. The method of analysis focuses on logical analysis and language analysis of moral language in the classic texts of Daoist ethics. The method of interpretation focuses on effective translation and understanding of moral language with unclear meaning in Daoist ethics. The method of comparison focuses on critical dialogue between ancient Daoist ethical thoughts and contemporary ethical theories and comparison between Confucian, Buddhist and Daoist ethics. Explaining the method of doing Daoist ethics clearly will promote the dialogue and understanding between Daoist ethics and contemporary ethics.

Wuwei (nonaction) is one of the core concepts of Daoist ethics. Edward Slingerland pointed out that wuwei involves a paradox, and Arthur C. Danto questioned whether wuwei could support a genuine moral theory and the idea of right action. To defend Daoist ethics and its concept of right action, it is necessary to envisage Danto’s criticism and the problems raised by Slingerland. According to Ivanhoe, Wuwei is not a paradox, but a riddle or mystery about self-cultivation. He thinks that if people could find the trick to the riddle, they can realize Wuwei. Ivanhoe’s analysis failed. Nickolas Knightly argues that we must acknowledge the paradox of Wuwei squarely. Based on criticizing Ivanhoe’s and Knightly’s schemes, this paper further analyzes the strategies to deal with the paradox of Wuwei. Wuwei should be placed in a specific situation and context. Wuwei requires the agents to have the corresponding psychological motivation, which will not continuously interfere with the purpose of action. Wuwei, as the behavior evaluation word of Daoist ethics, corresponds to moral anti-realism and nonassertive moral abolitionism.