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The design of high‐energy‐density batteries is the future goal of research on Li‐ion batteries. Halide‐type solid‐state electrolytes (SSEs) exceed their counterparts in terms of their stability at high potential. In this minireview, we discuss the developments in the work on halide‐type SSEs for all‐solid‐state Li batteries. In particular, we focus on the Li3InCl6structure. The effect of synthesis routes on this structure, as well as the convertible products resulting from its phase changes, is discussed. Conductivity can be increased and the electrochemical window can be improved through doping with different materials. Our review aims to provide readers with an overview of the stability and degradation of Li3InCl6SSE and the structure of halide‐type SSEs (Li–M–X, where M is a metal and X is a halogen). Using Li3InCl6as the solid‐state electrolyte is promising for future development. Halide SSEs exceed their counterparts by stability at high potential.

Limiting the carbon emission to the atmosphere requires the efficient utilization of carbonaceous gases and their capture via well‐designed platforms. Metal–CO2batteries are currently being demonstrated as the route to utilize CO2and produce energy simultaneously. In particular, Na–CO2batteries are considered an alternative to Li‐batteries because of their abundance and low cost. In the current review, the developments in the field of Na–CO2batteries are discussed. Carbon dioxide reactions to the decomposition of discharge products have been discussed elaborately. The main discharge products of Na–CO2batteries are Na2CO3and C. In the current review, various strategies are discussed to decompose the discharge products and hence improve cycle stability. The fraction of CO2has a substantial influence on cell cycles. A plausible route of battery reaction can be drawn with the help of an ex situ analysis of the electrodes. The final part of the review focuses on the use of solid‐state Na‐ion conductors in Na–CO2batteries. NA–CO2batteries are considered alternative to Li‐batteries because of their abundance and low cost. The main discharge products of NA–CO2batteries are NA2CO3and C. In the current review, various strategies are discussed to decompose the discharge products and hence improve cycle stability.

Alkali metal–carbon dioxide (Li/Na–CO2) batteries have generated widespread interest in the past few years owing to the attractive strategy of utilizing CO2while still delivering high specific energy densities. Among these systems, Na–CO2batteries are more cost effective than Li–CO2batteries 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–CO2and Na–CO2batteries. The potential of Na–CO2batteries as a viable energy storage technology was demonstrated.

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.

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 Li6.4La3Zr1.4Ta0.6O12nanosize powder and built a PCE interphase, which enhanced the interfacial stability between Li1.5Al0.5Ge1.5(PO4)3and 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.

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–2at 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–1and 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.

The large-scale application of rechargeable batteries in electric vehicles and energy-storage systems is still hindered by their high cost, particularly from the active materials. Here we proposed a concept of integration of extraction-separation and materials-preparation to further reduce the materials' cost. The power of this concept was demonstrated by the large-scale room-temperature synthesis (150 g per batch) of multi-shelled Na3(VOPO4)2F microspheres based on in situgenerated bubbles as soft templates. The as-prepared Na3(VOPO4)2F shows superior rate capability with discharge capacity of 81 mAh g−1at 15 C current rate and capacity retention of 70% after 3,000 cycles. Ex situUV-vis was first employed to characterize the variation of oxidation state for vanadium during the charging and discharging process. This is the first report of a rapid and facile large-scale room-temperature controllable synthesis of Na3(VOPO4)2F microspheres, and this approach could be extended to synthesize other similar compounds.

Utilizing CO2as cathode gas, Na–CO2battery has been intensively studied due to its potential application in the exploration of Mars, where CO2takes up 96% of the atmosphere. However, evaporation of the flammable liquid electrolyte restricts the practical application of the Na–CO2battery. Herein, a solid-state Na–CO2battery has been fabricated with the help of a plastic crystal electrolyte and kinetically stable interphase. The succinonitrile-based plastic crystal electrolyte interphase makes an intimate contact between Na3Zr2Si2PO12(NZSP) and cathode, thereby promotes the interfacial charge transfer. Simultaneously, the kinetically stable interphase on the anode side is revealed by the cooperation of theoretical calculation and experiments. The kinetically stable interphase protects the NZSP from the continuous interfacial parasitic reaction. The as-proposed solid-state Na–CO2battery delivers a life span of 50 cycles at 100 mA g−1with a potential gap of 1.4 V. This study makes solid-state electrolyte Na–CO2battery an attractive prospect in future applications.

Clean energy is an utmost need for the betterment of society. Li-ion batteries (LIBs) have been the clean-energy choice for several decades. However, with the increasing demand for batteries with high specific energy, the current state-of-the-art LIB technology is becoming unsatisfactory because of the capacity fade and low potential window encountered when using liquid-based electrolytes. Conversely, solid Li-ion conductors are capable of widening the cell-potential window and adding safety features to the LIB system. Nevertheless, the development of all-solid-state batteries (ASSBs) faces several challenges, starting from ion transport through solid components to interface reactions, leading to increased cell resistance. The current review focuses on the use of in situ/operandotechniques to explore such challenges in ASSBs. X-ray and neutron diffraction techniques can be used to evaluate the phase evolution and impurity formation in solid Li-ion conductors. Energy-dispersive X-rays can provide information about intermittent products during the battery cycle. Imaging techniques can provide direct visualization of changes that occur in cell components during cycles. Operandotechniques are further discussed to estimate the residual gas evolution in such ASSBs. Overall, this review discusses the cause of cell death and capacity fade in ASSBs.

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|LiFePO4and Li|Li–Pt|LLZTO|LiMn0.8Fe0.2PO4achieved 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.

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 CO2reduction 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 viacarbon 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–Nxsites 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–1at 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.

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)3solid-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–1and 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–1with a cutoff capacity of 500 mA h g–1. Solid-state lithium–carbon dioxide batteries have shown promising potential applications for future energy storage.

Nitrogen-coordinated single-atom catalysts (SACs) catalyzed electrochemical reduction of CO2(CO2RR) to CO has emerged as a promising strategy in the management of the global carbon cycle. Herein, we carried out density functional theory (DFT) calculations to investigate the role of possible Ni-Nxand Ni–C4coordinations in CO2RR catalysis. We discover that the free energy change for CO2RR is lowered with a decrease in Ni-Nxcoordination number, with Ni–C4displaying the lowest overpotential for CO2RR. Using these findings, we develop an effective strategy to transform Ni–N4to Ni–C4active sites by removing N moieties within Ni embedded in a hollow nitrogen-doped carbon shell (Ni@NCH). We demonstrate an improvement in CO selectivity with this transformation of active sites and the optimized Ni@NCH-1000 catalyst is capable of converting CO2to CO with high Faradaic efficiency for CO (FECO) of 96% and a current density (j) of −35 mA cm−2at an applied potential of −1 V vs Reversible Hydrogen Electrode (RHE). When adopted in a high-throughput gas diffusion electrolyzer, the newly-developed superhydrophobic catalyst is capable of maintaining CO selectivity >95% over a wide range of applied cell voltages from 2.4 V to 3 V with high current densities (~100 mA cm−2at 3 V). Our insights and findings with active site transformation in Ni–N–C SACs can serve as guidelines for designing highly active SACs for large-scale CO2RR systems.