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Jow-Lay Huang, Chi-Cheng Chiu, Shih-Yang Lin, Chin-Lung Kuo, Duy Khanh Nguyen, Ngoc Thanh Thuy Tran, Wen-Dung Hsu, Chia-Chin Chang, Jeng-Shiung Jan, Hsisheng Teng, Chia-Yun Chen, I-Ming Hung, Peter Chen, Yuh-Lang Lee, and Ming-Fa Lin
Energy, which is used in everyday living, can be saved in various forms, such as chemical batteries,1 solar electromagnetic fields,2 hydrogen,3 flowing water,4 blowing wind,5 radiative atoms,6 oil mines,6 oil gas,6 and coal mines.7 To greatly reduce the environmental impact, plenty of theoretical and experimental studies have been done for developing the various green energy materials.8–10 For example, the up-to-date well-established potential applications cover the battery-driven cell phones11 and electric vehicles,12 the solar-cell factories,13 the hydrogen-based buses,14 water-generated electric power,15 and the wind turbines.16 Specifically, this book is focused on lithium-ion batteries (LIBs),17 dye-sensitized solar cells,18 and perovskite solar cells.19 Furthermore, how to design and fabricate the electronic and optical devices with excellent performance, low cost, light weight, high safety, long lifetime, operating at a controllable temperature, and suitable voltage range are the main issues.20 The distinct theoretical models are proposed/developed to fully comprehend the diverse physical, chemical, and material phenomena. According to the previous studies, the molecular dynamics simulations,21 the first-principle calculations under the local charge density approximations,22 and the neutral network methods23 are available in thoroughly exploring the fundamental properties and solving the critical issues. As for LIBs, detailed analyses will be conducted on the anode materials accompanied with the chemical modified electrolytes and the significant additives,24 and the different functional polymer binders.25 On the experimental side, the successful syntheses of the emergent materials;26 the high-resolution measurements on geometric, electronic, optical, and transport properties;27 and the delicate examinations on the battery performance and the photon-to-electron conversion efficiency28 will be finished under a series of systematic studies. Detailed comparisons between the experimental measurements and the theoretical predictions are also made. Part of the inconsistency arising from them become new and open issues proposed in the contents.
Developing functional polymer binders for LIB cathodes and anodes has drawn much attention for improving LIB capacity, due to their low overall content yet critical role at the electrode interface. One of the widely applied commercial binders for LIBs is poly(vinylidene difluoride) (PVDF) for its good electrochemical stability and adhesive properties. Yet PVDF binder is an inert conductor of lithium ions (Li+), leading to high polarization resistance near the LIB electrode at a high charging/discharging rate. Hence, introducing ion-conducting polymers such as PEO and PAN into binder development is one of the common strategies to enhance the overall performance of LIBs. Gong et al.38 applied PAN as binders for various anode materials, including graphite, Li4Ti5O12, and Si/C, and showed improved adhesion, reduced charge transfer resistance, and enhanced capacity endurance. More recently, Tsao et al. utilized PEO-b-PAN copolymer as LiFePO4 cathode binder for LIB and this showed an improved charge transfer resistance and high-capacity retention under a high C-rate. Another study by the same group developed a water-borne binder of fluorinated copolymer functionalized with PEO featuring small impedance during charging and discharging.29 A novel PEDOT:PSS developed by Das et al. as LiFePO4 cathode binders showed improved LIB capacities after a cycling test. Note that current studies have utilized various complex formulas such as polymer blends or copolymers, making it difficult to identify the molecular effects of each functional polymer. Also, the detailed mechanisms of the aforementioned novel functional polymers on affecting Li+ transports at the electrode interface may differ from polymer electrolyte and thus remain elusive.
Graphite, in which graphene layers are periodically arranged along the z-direction, has been extensively utilized in everyday living for a long time. Three kinds of typical stacking configurations have been successfully identified from the experimental measurements. There exist AAA, ABA, and ABC stackings, namely, the simple hexagonal, Bernal, and rhombohedral graphites. The second one dominates in natural graphite, while the third one only corresponds to the partial system. Apparently, the theoretical and experimental studies on them show a lot of unusual fundamental properties (e.g., electronic properties,30 magnetic quantization,31 optical absorption, and reflectance spectra32,33) and transport properties.34 All pristine graphites belong to the semimetals,35 mainly owing to the interlayer atomic interactions of C-2pz orbitals. Their interlayer attractive forces mainly originate from the van der Waals interactions. They are weak but significant; therefore, many different guest atoms/ions are easily intercalated into the graphitic spacings. On the other side, alkali atoms can create active chemical environments to form the critical interactions with other atoms or molecules, since each of them possesses an s-state electron in the outmost orbital. They are suitable for serving as guest atoms intercalated into the layered graphite, leading to a very high electrical conductivity.36 Up to now, the stage-n alkali graphite-intercalation compounds have been successfully synthesized except for Na guest atoms. Apparently, there are important differences between Li and other alkali atoms (M = K, Rb, Cs). For example, the stage-1 systems are, respectively, LiC6 and MC8 with the distinct unit cell. In particular, the stacking configuration of the neighboring graphitic layers is AAA or ABA, being sensitive to the type and concentration of alkali atoms.37 As to the intercalation and deintercalation of Li+ ions in graphite, such actions might appear frequently in th...
