1,2,3-Tris (2-cyanoethoxy) propane (TPPN) as a new electrolyte additive has been investigated in 4.55 V high voltage lithium cobaltate (LiCoO₂) /graphite pouch cells. By comparing the cycle performance of cells without and with TPPN, it is found that the addition of TPPN can improve the performance, and the optimal weight proportion is 2%. At 3.00-4.55 V and 1C/1C, the cells with 2%TPPN has a capacity retention rate of 86.4% at 25℃ for 900 cycles compared with the capacity retention rate of 8.7% that without 2%TPPN. According to the theoretical calculation and linear sweep voltammetry, the decomposition of TPPN is preferred to that of the electrolyte solvent. It can be seen from N 1s spectra from X-ray photoelectron spectroscopy on LiCoO₂ surface that TPPN forms an interfacial film on the LiCoO₂ surface. It can be seen from the impedance data that the interface film formed by TPPN has low impedance and high stability. From theoretical calculation, scanning, transmission electron microscopy, X-ray diffraction on LiCoO₂ surface and Co 2p spectra from X-ray photoelectron spectroscopy on graphite surface, it is revealed that the interface film formed by TPPN can effectively suppress the decomposition of electrolyte and the dissolution of cobalt ions, confirming the high stability of the interface film formed by TPPN.

The development of low-cost, highly stable, and catalytically active oxygen reduction reaction (ORR) non-precious metal catalysts is essential for fuel cells and metal-air batteries applications. In this study, the one-step synthesis of composite catalysts of ZnFe nanoparticles embedded with nitrogen and sulfur doped carbon nanotubes (ZnS-FeS-Fe₃C/S, NCNT) was reported using ZIF-8 as precursor. The sample of ZFF/S, NCNT-8 after the optimal calcination temperature was determined by electrochemical tests to be onset potential of 0.99 V vs. RHE and a half-wave potential of 0.84 V vs. RHE, as well as a good methanol tolerance and long-term durability comparable to commercial Pt/C. It is also proposed that S, N co-doped carbon nanotube (CNT) and additional ZnS, FeS and Fe₃C providing active sites can enhance the ORR catalytic performance. The in-situ growth CNT method used in the study can provide ideas for the preparation of cathode catalysts for fuel cells and metal-air batteries.

Sodium metal is a promising high specific capacity anode material for sodium batteries. However, it faces critical challenges including dendrite growth and volumetric expansion. These issues lead to reduced coulombic efficiency, internal short circuits, and safety problem. This study demonstrates a three-dimensional sodium alloy composite anode fabricated through a high-temperature fusion. SnF₂-coated carbon cloth (CC) is contacted with molten sodium, triggering a reaction between SnF₂ and molten sodium to form NaF and Na-Sn alloy. Subsequently, the molten sodium infiltrates the carbon cloth via capillary action. The composite anode, using carbon cloth as a current collector, features a hierarchical architecture integrating NaF and Na-Sn alloy. This design aims to mitigate dendritic growth and volume expansion of sodium metal anodes. The NaF layer stabilizes the solid electrolyte interphase (SEI) , mitigates electrolyte corrosion, and homogenizes ion flux distribution. Meanwhile, the Na-Sn alloy provides abundant active sites for sodium deposition, enhancing uniformity of deposition. During cycling, the carbon cloth ensures structural integrity of the composite anode. Consequently, the composite anode of NaF-coated Na-Sn alloy/carbon cloth (NaF/Na/Na-Sn@CC) demonstrates exceptional cycling stability. Compared with conventional sodium metal anodes, symmetric cells with composite anodes exhibit stable cycling for 700 hours with a significantly low overpotential. The full cells with the composite anodes enable stable cycling over 400 cycles at an elevated rate of 20 C.

Constructing the magnesium alloy with fine grains, low density of dislocations, and weak crystal orientation is of crucial importance to enhance its comprehensive performance as the anode for Mg-air battery. However, this unique microstructure can hardly be achieved with conventional plastic deformation such as rolling or extrusion. Herein, we tailor the microstructure of Mg-Al-Sn-RE alloy by using the friction stir processing, which obviously refines the grains without increasing dislocation density or strengthening crystal orientation. The Mg-air battery with the processed Mg-Al-Sn-RE alloy as the anode exhibits higher discharge voltages and capacities than that employing the untreated anode. Furthermore, the impact of friction stir processing on the electrochemical discharge behaviour of Mg-Al-Sn-RE anode and the corresponding mechanism are also analysed according to microstructure characterization and electrochemical response.

Composite polymer electrolyte is one of the most promising electrolyte candidates for future solid state lithium batteries, but inorganic fillers used are prone to an agglomeration, thus being difficult to form a continuous ion transport pathway. Flexible SiO₂ nanofiber porous membranes were fabricated by an electrospinning technique and a heating treatment process. The samples were characterized by scanning electron microscope, fourier transform infrared spectrometer, X-ray diffractometer, and thermogravimetry analyzer. The effects of TEOS proportion and polymer concentration in electrospinning precursor on the morphology and flexibility of the nanofiber porous membranes were investigated. Moreover, the electrochemical properties of PEO based composite polymer electrolyte (CPE-SiO₂) were analyzed. The ionic conductivity of this composite electrolyte can reach 2.52×10^–5 S/cm at 30 ℃. LiFePO₄|CPE-SiO₂|Li can be steadily charged/discharged for 50 times at 1 C rate and 60 ℃. Li|CPE-SiO₂|Li symmetric cell can keep a stable overpotential profile for 300 h with a low hysteresis at 60 ℃. This work provides an effective approach for the commercialization of next generation high-performance all-solid-state batteries.