Inorganic Composition Modulation of Solid Electrolyte Interphase for Fast Charging Lithium Metal Batteries.

The solid electrolyte interphase (SEI) with lithium fluoride (LiF) is critical to the performance of lithium metal batteries (LMBs) due to its high stability and mechanical properties. However, the low Li ion conductivity of LiF impedes the rapid diffusion of Li ions in the SEI, which leads to localized Li ion oversaturation dendritic deposition and hinders the practical applications of LMBs at high-current regions (>3 C). To address this issue, a fluorophosphated SEI rich with fast ion-diffusing inorganic grain boundaries (LiF/Li3P) is introduced. By utilizing a sol electrolyte that contains highly dispersed porous LiF nanoparticles modified with phosphorus-containing functional groups, a fluorophosphated SEI is constructed and the presence of electrochemically active Li within these fast ion-diffusing grain boundaries (GBs-Li) that are non-nucleated is demonstrated, ensuring the stability of the Li || NCM811 cell for over 1000 cycles at fast-charging rates of 5 C (11 mA cm-2). Additionally, a practical, long cycling, and intrinsically safe LMB pouch cell with high energy density (400 Wh kg-1) is fabricated. The work reveals how SEI components and structure design can enable fast-charging LMBs.

Litter traps: A comparison of four marine habitats as sinks for anthropogenic marine macro-litter in Singapore.

The potential for marine litter being trapped in biodiverse marine habitats such as mangrove forests, seagrass meadows and coral reefs is poorly understood. This study presents the first comprehensive investigation on the status of macro-litter across four marine habitats in Singapore during the two monsoonal seasons. Overall, litter density did not vary considerably between the southwest and the northeast monsoon. The litter density in terms of count was generally lower in seagrass meadows and coral reefs compared to mangroves and beaches. Plastic was the major type of litter found across most habitat types. Notably, many fishing-related items were found on coral reefs, while drinking straws were abundant at the mangrove strandlines during the southwest monsoon. Foam fragments and cigarette butts were common at the beach strandlines. These results suggest that mangroves among other habitats examined here should be prioritised for clean-up efforts in order to restore these critical coastal habitats.

Trace Doping of Multiple Elements Enables Stable Cycling of High Areal Capacity LiNi0.5 Mn1.5 O4 Cathode.

High-voltage spinel cobalt-free LiNi0.5 Mn1.5 O4 (LNMO) is one of the most promising cathode candidates for next-generation lithium-ion batteries (LIBs) due to its high specific capacity, high operating voltage, and low cost. However, inferior electronic conductivity, transition metal dissolution, and fast capacity degradation of LNMO, especially in high mass loading for high areal capacity, are the critical material challenges for its practical application. Herein, trace multiple Cr-Fe-Cu elements doping of LiNi0.45 Cr0.0167 Fe0.0167 Cu0.0167 Mn1.5 O4 (CFC0.5-LNMO) cathode is achieved by a blow-spinning strategy to exhibit very stable cycling at a practical level of areal capacity up to 3 mAh cm-2 . It is demonstrated that the Cu, Fe, and Cr doping into the LNMO lattice can suspend the Mn dissolution and improve the Li ion diffusivity and electronic conductivity of the LNMO host. As a result, the obtained CFC0.5-LNMO cathode exhibits an excellent rate performance (1.75 mAh cm-2 at 1C) and long cycling stability under an areal capacity of 3 mAh cm-2 (78% capacity retention over 300 cycles at 0.5C).

Lithium Fluoride in Electrolyte for Stable and Safe Lithium-Metal Batteries.

Electrolyte engineering via fluorinated additives is promising to improve cycling stability and safety of high-energy Li-metal batteries. Here, an electrolyte is reported in a porous lithium fluoride (LiF) strategy to enable efficient carbonate electrolyte engineering for stable and safe Li-metal batteries. Unlike traditionally engineered electrolytes, the prepared electrolyte in the porous LiF nanobox exhibits nonflammability and high electrochemical performance owing to strong interactions between the electrolyte solvent molecules and numerous exposed active LiF (111) crystal planes. Via cryogenic transmission electron microscopy and X-ray photoelectron spectroscopy depth analysis, it is revealed that the electrolyte in active porous LiF nanobox involves the formation of a high-fluorine-content (>30%) solid electrolyte interphase layer, which enables very stable Li-metal anode cycling over one thousand cycles under high current density (4 mA cm-2 ). More importantly, employing the porous LiF nanobox engineered electrolyte, a Li || LiNi0.8 Co0.1 Mn0.1 O2 pouch cell is achieved with a specific energy of 380 Wh kg-1 for stable cycling over 80 cycles, representing the excellent performance of the Li-metal pouch cell using practical carbonate electrolyte. This study provides a new electrolyte engineering strategy for stable and safe Li-metal batteries.

Blow-Spinning Enabled Precise Doping and Coating for Improving High-Voltage Lithium Cobalt Oxide Cathode Performance.

Lithium cobalt oxide (LiCoO2) possesses an attractive theoretical specific capacity (274 mAh g-1) and high discharge voltage (∼4.2 V vs Li+/Li). However, only a half of the theoretical capacity of LiCoO2 is available in commercialized lithium ion batteries because of the intrinsic structural instability and detrimental interface of LiCoO2 at the charging voltage over 4.2 V. Here, a facile blow-spinning synthetic method is developed to realize precise doping and simultaneous self-assembly coating of LiCoO2 particles, achieving a record performance among present LiCoO2 cathodes. Owing to the spatial confinement effect of microfibers fabricated by blow-spinning, homogeneously Mn and La doped in the LiCoO2 host and uniformly Li-Ti-O segregated at the LiCoO2 surface can be realized in every batch of samples. It is demonstrated that the Mn and La codoping can suspend the intrinsic instability and increase the Li+ diffusivity of the LiCoO2 host, and the Ti-based coating can stabilize the interface of LiCoO2 particles at the charging voltage up to 4.5 V. As a result, the obtained comodified LiCoO2 cathode shows the best rate performance (1.85 mAh cm-2 at 2C) and longest cycling stability under an areal capacity of 2.04 mAh cm-2 (83% capacity retention over 300 cycles at 0.3C), in comparison to previously reported LiCoO2 cathodes.

A Nacre-Inspired Separator Coating for Impact-Tolerant Lithium Batteries.

The commercial ceramic nanoparticle coated microporous polyolefin separators used in lithium batteries are still vulnerable under external impact, which may cause short circuits and consequently severe safety threats, because the protective ceramic nanoparticle coating layers on the separators are intrinsically brittle. Here, a nacre-inspired coating on the separator to improve the impact tolerance of lithium batteries is reported. Instead of a random structured ceramic nanoparticle layer, ion-conductive porous multilayers consisting of highly oriented aragonite platelets are coated on the separator. The nacre-inspired coating can sustain external impact by turning the violent localized stress into lower and more uniform stress due to the platelet sliding. A lithium-metal pouch cell using the aragonite platelet coated separator exhibits good cycling stability under external shock, which is in sharp contrast to the fast short circuit of a lithium-metal pouch cell using a commercial ceramic nanoparticle coated separator.

A fluorinated alloy-type interfacial layer enabled by metal fluoride nanoparticle modification for stabilizing Li metal anodes.

Using highly dispersed metal fluoride nanoparticles to construct a uniform fluorinated alloy type interfacial layer on the surface of Li metal anodes is realized by an ex situ solution chemical modification method. The fluorinated alloy-type interfacial layer can effectively inhibit the growth of undesirable Li dendrites while enhancing the performance of Li metal anodes.

High Voltage Magnesium-ion Battery Enabled by Nanocluster Mg3Bi2 Alloy Anode in Noncorrosive Electrolyte.

Currently, developing high voltage (beyond 2 V) rechargeable Mg-ion batteries still remains a great challenge owing to the limit of corrosive electrolyte and low compatibility of anode material. Here we report a facile one step solid state alloying route to synthesize nanoclustered Mg3Bi2 alloy as a high-performance anode to build up a 2 V Mg-ion battery using noncorrosive electrolyte. The fabricated nanoclustered Mg3Bi2 anode delivers a high reversible specific capacity (360 mAh g-1) with excellent stability (90.7% capacity retention over 200 cycles) and high Coulombic efficiency (average 98%) at 0.1 A g-1. The good performance is attributed to the stable nanostructures, which effectively accommodate the reversible Mg2+ ion insertion/deinsertion without losing electric contact among clusters. Significantly, the nanoclustered Mg3Bi2 anode can be coupled with high voltage cathode Prussian Blue to assemble a full cell using noncorrosive electrolyte, showing a stable cycling (88% capacity retention over 200 cycles at 0.2 A g-1) and good rate capability (103 mAh g-1 at 0.1 A g-1 and 58 mAh g-1 at 2 A g-1). The energy and power density of the as-fabricated full cell can reach up to 81 Wh kg-1 and 2850 W kg-1, respectively, which are both the highest values among the reported Mg-ion batteries using noncorrosive electrolytes. This study demonstrates a cost-effective route to fabricate stable and high voltage rechargeable Mg-ion battery potentially for grid-scale energy storage.

A novel method for creating working space during endoscopic thyroidectomy via bilateral areolar approach.

BACKGROUND: Endoscopic thyroidectomy (ET) can be performed through the bilateral areolar approach (BAA). A working space (WS) is typically created on the surface of the pectoral fascia in the chest wall and in the subplatysmal space in the neck. There are several limitations of using this WS. The aim of this study was to establish a new WS for ET. SUBJECTS AND METHODS: A retrospective review was performed on 85 patients with benign thyroid nodules who had undergone ET through a BAA. A WS was created between the anterior and poster layers of the superficial pectoral fascia (SPF) in the chest and underneath the deep layer of the investing layer (IL) in the neck. RESULTS: The time for creating the WS was 7.2 ± 2.1 (range, 5-12) minutes. No hemorrhage occurred during the procedure. Fat liquefaction occurred in 2 patients. Edema of the neck skin flap presented as lack of a suprasternal notch. No skin numbness occurred. No patient required postoperative pain medication. All patients were extremely satisfied with the cosmetic results. CONCLUSIONS: This new method of establishing a WS between the two layers of the SPF and underneath the IL is simple and fast, provides good exposure, yields less postoperative pain, and has a lower risk of skin burn.

A new method of spermatic cord mobilization in herniorrhaphy.

Spermatic cord mobilization is a routine part of inguinal hernia repair, but the method of cord mobilization varies among surgeons. This study establishes an anatomic plane for spermatic cord mobilization. We studied the anatomy of the superficial cremasteric fascia in 105 male patients during herniorrhaphy for primary inguinal hernias. The mean patient age was 44.8 (18-71) years and mean body mass index was 24.1 kg/m(2) (21.5-27.1 kg/m(2)). The two layers of the superficial cremasteric fascia between the spermatic cord and the inguinal falx were incised to mobilize the cord. We found that spermatic cord mobilization during herniorrhaphy can be easily approached through an anatomic plane between the spermatic cord and the conjoined tendon with subsequent division of the superficial cremasteric fascia. None of the patients experienced any hemorrhage or nerve injury during cord mobilization. We found this method to be both safe and easy to learn.