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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.

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.

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.

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.

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.