Engineering Cathode-Electrolyte Interface of High-Voltage Spinel LiNi0.5Mn1.5O4 via Halide Solid-State Electrolyte Coating.

The high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) cathode material with high energy density, low cost, and excellent rate capability has grabbed the attention of the field. However, a high-voltage platform at 4.7 V causes severe oxidative side reactions when in contact with the organic electrolyte, leading to poor electrochemical performance. Furthermore, the contact between the liquid electrolyte and LNMO leads to Mn dissolution during cycles. In this work, we applied the sol-gel method to prepare Li3InCl6-coated LNMO (LIC@LNMO) to address the mentioned problems of LNMO. By introducing a protective layer of halide-type solid-state electrolyte on LNMO, we can prevent direct contact between LNMO and electrolyte while maintaining good ionic conductivity. Thus, we could demonstrate that 5 wt % LIC@LNMO exhibited a good cycle performance with a Coulombic efficiency of 99% and a capacity retention of 80% after the 230th cycle at the 230th cycle at 1C at room temperature.

Controlling Cell Components to Design High-Voltage All-Solid-State Lithium-Ion Batteries.

All-solid-state batteries with solid ionic conductors packed between solid electrode films can release the dead space between them, enabling a greater number of cells to stack, generating higher voltage to the pack. This Review is focused on using high-voltage cathode materials, in which the redox peak of the components is extended beyond 4.7 V. Li-Ni-Mn-O systems are currently under investigation for use as the cathode in high-voltage cells. Solid electrolytes compatible with the cathode, including halide- and sulfide-based electrolytes, are also reviewed. Discussion extends to the compatibility between electrodes and electrolytes at such extended potentials. Moreover, control over the thickness of the anode is essential to reduce solid-electrolyte interphase formation and growth of dendrites. The Review discusses routes toward optimization of the cell components to minimize electrode-electrolyte impedance and facilitate ion transportation during the battery cycle.

Highly Efficient Hydrogen Evolution from Seawater by Biofunctionalized Exfoliated MoS2 Quantum Dot Aerogel Electrocatalysts That Is Superior to Pt.

As a source of clean and sustainable energy, reliable hydrogen production requires highly efficient and stable electrocatalysts. In recent years, molybdenum disulfide (MoS2) has been demonstrated as a promising electrocatalyst for hydrogen evolution reactions (HERs). Here, we demonstrate that a three-dimensional (3D) MoS2 quantum dot (MoS2QD) aerogel is an efficient cathode electrocatalyst that can be used to enhance the HER in acid, neutral, and alkaline (e.g., real seawater) environments. In studying the effects of the exfoliated MoS2 dimension for the HER, we found that the biofunctionalized exfoliated MoS2QD shows much higher cathodic density, a more lower energy input, and a lower Tafel slope for the HER than the larger size of the chlorophyll-assisted exfoliated MoS2, highlighting the importance of the size of the MoS2 aerogel support for accelerating the HER performance. Moreover, the electrocatalytic activity of MoS2QD-aerogel is superior to that of Pt in neutral conditions. In real seawater, the MoS2QD-aerogel sample exhibits stable HER performance after consecutive scanning for 150 cycles, while the HER activity of the Pt dramatically decreases after 50 cycles. These results showed for the first time how the 3D MoS2 configuration in MoS2 aerogel can be used to effectively produce hydrogen for clean energy applications.