Constructing LiF-Dominated Interphases with Polymer Interwoven Outer Layer Enables Long-Term Cycling of Si Anodes

Constructing a robust solid electrolyte interphase (SEI) is extremely critical to developing high-energy-density silicon (Si)-based lithium-ion batteries. However, it is still elusive how to accurately manipulate the chemical composition and structure of the SEI layer. Herein, a LiF-dominated SEI film intertwined by a highly elastic polymer is achieved by regulating the defluorination mechanism of the fluorinated carbonate additive on the Si electrode surface. The experimental and computational results confirm that the decomposition route of trans-difluoroethylene carbonate (DFEC) molecules can be significantly altered in the presence of lithium difluoro(oxalato)borate (LiDFOB) additive. The induction of direct defluorination of DFEC step by LiDFOB, as opposed to the breaking of C–O bonds without LiDFOB addition, is crucial in ensuring the exclusive formation of LiF-dominated SEI and maintaining the cyclic structure of DFEC. The defluorinated DFEC easily polymerizes to form poly(vinylene carbonate), enhancing the elasticity of the SEI. The resulting LiF-dominated SEI film with a polymer interwoven outer layer shows enhanced ionic conductivity and mechanical stability, which can effectively accelerate electrode reaction kinetics and maintain the structural stability of the Si electrode. As a result, the Si electrode with the electrolyte containing the designed dual-additive exhibits superior cycling stability and excellent rate performance, delivering a high reversible capacity of 1487.3 mAh g–1 after 1000 cycles at 2 A g–1

Table1_Case report: Epigastric heteropagus twins and literature review.pdf

Epigastric heteropagus twins are an extremely rare congenital anomaly of conjoined twins. We present a case of epigastric heteropagus twins who were diagnosed via prenatal ultrasound imaging: the fetus (or host) was connected to the abdominal wall of the parasite (the dependent portion), and an omphalocele was present. The male infant was delivered by cesarean section at 35 + 5 weeks gestation. The parasite lacked a head and heart and presented long bones of the limbs. After abdominal computed tomography, omphalocele repair, and parasite removal were surgically performed under general anesthesia. After discharge (follow-up, 3 months), the infant is currently growing well and is healing satisfactorily. Forty-one cases of epigastric heteropagus twins were retrieved from database searches: 38 good postoperative outcomes, 2 perioperative deaths, and 1 termination. The case highlights that even when parasites are massive in size, births can present good outcomes with suitable surgical treatment.</p

(101) Plane-Oriented SnS₂ Nanoplates with Carbon Coating: A High-Rate and Cycle-Stable Anode Material for Lithium Ion Batteries

Tin disulfide is considered to be a promising anode material for Li ion batteries because of its high theoretical capacity as well as its natural abundance of sulfur and tin. Practical implementation of tin disulfide is, however, strongly hindered by inferior rate performance and poor cycling stability of unoptimized material. In this work, carbon-encapsulated tin disulfide nanoplates with a (101) plane orientation are prepared via a facile hydrothermal method, using polyethylene glycol as a surfactant to guide the crystal growth orientation, followed by a low-temperature carbon-coating process. Fast lithium ion diffusion channels are abundant and well-exposed on the surface of such obtained tin disulfide nanoplates, while the designed microstructure allows the effective decrease of the Li ion diffusion length in the electrode material. In addition, the outer carbon layer enhances the microscopic electrical conductivity and buffers the volumetric changes of the active particles during cycling. The optimized, carbon coated tin disulfide (101) nanoplates deliver a very high reversible capacity (960 mAh g^–1 at a current density of 0.1 A g^–1), superior rate capability (796 mAh g^–1 at a current density as high as 2 A g^–1), and an excellent cycling stability of 0.5 A g^–1 for 300 cycles, with only 0.05% capacity decay per cycle

MoS₂ Nanosheets Vertically Grown on Graphene Sheets for Lithium-Ion Battery Anodes

A designed nanostructure with MoS₂ nanosheets (NSs) perpendicularly grown on graphene sheets (MoS₂/G) is achieved by a facile and scalable hydrothermal method, which involves adsorption of Mo₇O₂₄^6– on a graphene oxide (GO) surface, due to the electrostatic attraction, followed by <i>in situ</i> growth of MoS₂. These results give an explicit proof that the presence of oxygen-containing groups and pH of the solution are crucial factors enabling formation of a lamellar structure with MoS₂ NSs uniformly decorated on graphene sheets. The direct coupling of edge Mo of MoS₂ with the oxygen from functional groups on GO (C–O–Mo bond) is proposed. The interfacial interaction of the C–O–Mo bonds can enhance electron transport rate and structural stability of the MoS₂/G electrode, which is beneficial for the improvement of rate performance and long cycle life. The graphene sheets improve the electrical conductivity of the composite and, at the same time, act not only as a substrate to disperse active MoS₂ NSs homogeneously but also as a buffer to accommodate the volume changes during cycling. As an anode material for lithium-ion batteries, the manufactured MoS₂/G electrode manifests a stable cycling performance (1077 mAh g^–1 at 100 mA g^–1 after 150 cycles), excellent rate capability, and a long cycle life (907 mAh g^–1 at 1000 mA g^–1 after 400 cycles)