Spontaneous In Situ Formation of Lithium Metal Nitride in the Interface of Garnet-Type Solid-State Electrolyte by Tuning of Molten Lithium.

All-solid-state lithium-ion batteries (ASSLIBs) have attracted much attention owing to their high energy density and safety and are known as the most promising next-generation LIBs. The biggest advantage of ASSLIBs is that it can use lithium metal as the anode without any safety concerns. This study used a high-conductivity garnet-type solid electrolyte (Li6.75La3Zr1.75Ta0.25O12, LLZTO) and Li-Ga-N composite anode synthesized by mixing melted Li with GaN. The interfacial resistance was reduced from 589 to 21 Ω cm2, the symmetry cell was stably cycled for 1000 h at a current density of 0.1 mA cm-2 at room temperature, and the voltage range only changed from ±30 to ±40 mV. The full cell of Li-Ga-N|LLZTO|LFP exhibited a high first-cycle discharge capacity of 152.2 mAh g-1 and Coulombic efficiency of 96.5% and still maintained a discharge capacity retention of 91.2% after 100 cycles. This study also demonstrated that Li-Ga-N had been shown as two layers. Li3N shows more inclined to be closer to the LLZTO side. This method can help researchers understand what interface improvements can occur to enhance the performance of all-solid-state batteries in the future.

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.

Extensively Reducing Interfacial Resistance by the Ultrathin Pt Layer between the Garnet-Type Solid-State Electrolyte and Li-Metal Anode.

All-solid-state Li-ion batteries (ASSLIBs), also known as next-generation batteries, have attracted much attention due to their high energy density and safety. The best advantage of ASSLIBs is the Li-metal anodes that could be used without safety issues. In this study, a highly conductive garnet solid electrolyte (Li6.75La3Zr1.75Ta0.25O12, LLZTO) was used in the ASSLIB, and a Pt film was used to modify the surface of LLZTO to prove the solution of the Li-metal anode for LLZTO. Li-Pt alloy was synthesized to improve the wettability and contact of the interface. The interfacial resistance was reduced by 21 times, at only 9 Ω cm2. The symmetric cell could stably cycle over 3500 h at a current density of 0.1 mA cm-2. The full cell of Li|Li-Pt|LLZTO|LiFePO4 and Li|Li-Pt|LLZTO|LiMn0.8Fe0.2PO4 achieved high stability in terms of battery performance. Point-to-point contact transformed into homogeneous surface contact made the Li-ion flux faster and more stable. This surface modification method could provide researchers with a new choice for fixing interface issues and promoting the application of high-performance ASSLIBs in the future.

Effective Ru/CNT Cathode for Rechargeable Solid-State Li-CO2 Batteries.

An effective Ru/CNT electrocatalyst plays a crucial role in solid-state lithium-carbon dioxide batteries. In the present article, ruthenium metal decorated on a multi-walled carbon nanotubes (CNTs) is introduced as a cathode for the lithium-carbon dioxide batteries with Li1.5Al0.5Ge1.5(PO4)3 solid-state electrolyte. The Ru/CNT cathode exhibits a large surface area, maximum discharge capacity, excellent reversibility, and long cycle life with low overpotential. The electrocatalyst achieves improved electrocatalytic performance for the carbon dioxide reduction reaction and carbon dioxide evolution reaction, which are related to the available active sites. Using the Ru/CNT cathode, the solid-state lithium-carbon dioxide battery exhibits a maximum discharge capacity of 4541 mA h g-1 and 45 cycles of battery life with a small voltage gap of 1.24 V compared to the CNT cathode (maximum discharge capacity of 1828 mA h g-1, 25 cycles, and 1.64 V as voltage gap) at a current supply of 100 mA g-1 with a cutoff capacity of 500 mA h g-1. Solid-state lithium-carbon dioxide batteries have shown promising potential applications for future energy storage.

Designing Undercoordinated Ni-Nx and Fe-Nx on Holey Graphene for Electrochemical CO2 Conversion to Syngas.

In this study, we propose a top-down approach for the controlled preparation of undercoordinated Ni-Nx (Ni-hG) and Fe-Nx (Fe-hG) catalysts within a holey graphene framework, for the electrochemical CO2 reduction reaction (CO2RR) to synthesis gas (syngas). Through the heat treatment of commercial-grade nitrogen-doped graphene, we prepared a defective holey graphene, which was then used as a platform to incorporate undercoordinated single atoms via carbon defect restoration, confirmed by a range of characterization techniques. We reveal that these Ni-hG and Fe-hG catalysts can be combined in any proportion to produce a desired syngas ratio (1-10) across a wide potential range (-0.6 to -1.1 V vs RHE), required commercially for the Fischer-Tropsch (F-T) synthesis of liquid fuels and chemicals. These findings are in agreement with our density functional theory calculations, which reveal that CO selectivity increases with a reduction in N coordination with Ni, while unsaturated Fe-Nx sites favor the hydrogen evolution reaction (HER). The potential of these catalysts for scale up is further demonstrated by the unchanged selectivity at elevated temperature and stability in a high-throughput gas diffusion electrolyzer, displaying a high-mass-normalized activity of 275 mA mg-1 at a cell voltage of 2.5 V. Our results provide valuable insights into the implementation of a simple top-down approach for fabricating active undercoordinated single atom catalysts for decarbonized syngas generation.

Comparative Study of Li-CO2 and Na-CO2 Batteries with Ru@CNT as a Cathode Catalyst.

Alkali metal-carbon dioxide (Li/Na-CO2) batteries have generated widespread interest in the past few years owing to the attractive strategy of utilizing CO2 while still delivering high specific energy densities. Among these systems, Na-CO2 batteries are more cost effective than Li-CO2 batteries because the former uses cheaper and abundant Na. Herein, a Ru/carbon nanotube (CNT) as a cathode material was used to compare the mechanisms, stabilities, overpotentials, and energy densities of Li-CO2 and Na-CO2 batteries. The potential of Na-CO2 batteries as a viable energy storage technology was demonstrated.

Interface Between Solid-State Electrolytes and Li-Metal Anodes: Issues, Materials, and Processing Routes.

Li metal, which has a high theoretical capacity and negative electrochemical potential, is regarded as the "holy grail" in Li-ion batteries. However, the flammable nature of liquid electrolyte leads to safety issues. Hence, the cooperation of solid-state electrolyte and Li-metal anode is demanded. However, the short cycle life induced by interfacial issues is the main challenge faced by their cooperation. In this review, dendrite and interfacial side reactions are comprehensively analyzed as the main interfacial problems. Meanwhile, the "state-of-the-art" interphase materials are summarized. The challenges faced by each kind of material are underscored. Moreover, different processing routes to fabricate artificial interphase are also investigated from an engineering perspective. The processing routes suitable for mass production are also underscored.

Matchmaker of Marriage between a Li Metal Anode and NASICON-Structured Solid-State Electrolyte: Plastic Crystal Electrolyte and Three-Dimensional Host Structure.

The marriage between a Li metal anode and the solid-state electrolyte is expected to limit the safety risk of secondary batteries. However, dendrites and interfacial stability hinder the combination of Li metal anode and solid-state electrolyte. Herein, a plastic crystal electrolyte (PCE) and three-dimensional (3D) host structure played the role of a matchmaker in combining the solid-state electrolyte and Li metal anode. Succinonitrile cooperated with Li salt and Li6.4La3Zr1.4Ta0.6O12 nanosize powder and built a PCE interphase, which enhanced the interfacial stability between Li1.5Al0.5Ge1.5(PO4)3 and Li metal anode. To protect the soft PCE from the dendrite penetration, commercially sold Super P, carbon nanotube, KS6, and Ketjen black were co-heated with the melted Li metal. However, only KS6 built a 3D host in Li metal successfully because of its high graphitization and layered structure. Benefitting from the matchmakers, the solid-state batteries exhibited enhanced cycling stability.