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The electrochemical CO2 conversion to formate is a promising approach for reducing CO2 level and obtaining value‐added chemicals, but its partial current density is still insufficient to meet the industrial demands. Herein, we developed a surface‐lithium‐doped tin (s‐SnLi) catalyst by controlled electrochemical lithiation. Density functional theory calculations indicated that the Li dopants introduced electron localization and lattice strains on the Sn surface, thus enhancing both activity and selectivity of the CO2 electroreduction to formate. The s‐SnLi electrocatalyst exhibited one of the best CO2‐to‐formate performances, with a partial current density of −1.0 A cm−2 for producing formate and a corresponding Faradaic efficiency of 92 %. Furthermore, Zn–CO2 batteries equipped with the s‐SnLi catalyst displayed one of the highest power densities of 1.24 mW cm−2 and an outstanding stability of >800 cycles. Our work suggests a promising approach to incorporate electron localization and lattice strain for the catalytic sites to achieve efficient CO2‐to‐formate electrosynthesis toward potential commercialization. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 conversion to formate is a promising approach for reducing CO2 level and obtaining value‐added chemicals, but its partial current density is still insufficient to meet the industrial demands. Herein, we developed a surface‐lithium‐doped tin (s‐SnLi) catalyst by controlled electrochemical lithiation. Density functional theory calculations indicated that the Li dopants introduced electron localization and lattice strains on the Sn surface, thus enhancing both activity and selectivity of the CO2 electroreduction to formate. The s‐SnLi electrocatalyst exhibited one of the best CO2‐to‐formate performances, with a partial current density of −1.0 A cm−2 for producing formate and a corresponding Faradaic efficiency of 92 %. Furthermore, Zn–CO2 batteries equipped with the s‐SnLi catalyst displayed one of the highest power densities of 1.24 mW cm−2 and an outstanding stability of >800 cycles. Our work suggests a promising approach to incorporate electron localization and lattice strain for the catalytic sites to achieve efficient CO2‐to‐formate electrosynthesis toward potential commercialization. [ABSTRACT FROM AUTHOR]

Solid‐state electrolytes (SEs) with high anodic (oxidation) stability are essential for achieving all‐solid‐state Li‐ion batteries (ASSLIBs) operating at high voltages. Until now, halide‐based SEs have been one of the most promising candidates due to their compatibility with cathodes and high ionic conductivity. However, the developed chloride and bromide SEs still show limited electrochemical stability that is inadequate for ultrahigh voltage operations. Herein, this challenge is addressed by designing a dual‐halogen Li‐ion conductor: Li3InCl4.8F1.2. F is demonstrated to selectively occupy a specific lattice site in a solid superionic conductor (Li3InCl6) to form a new dual‐halogen solid electrolyte (DHSE). With the incorporation of F, the Li3InCl4.8F1.2 DHSE becomes dense and maintains a room‐temperature ionic conductivity over 10−4 S cm−1. Moreover, the Li3InCl4.8F1.2 DHSE exhibits a practical anodic limit over 6 V (vs Li/Li+), which can enable high‐voltage ASSLIBs with decent cycling. Spectroscopic, computational, and electrochemical characterizations are combined to identify a rich F‐containing passivating cathode‐electrolyte interface (CEI) generated in situ, thus expanding the electrochemical window of Li3InCl4.8F1.2 DHSE and preventing the detrimental interfacial reactions at the cathode. This work provides a new design strategy for the fast Li‐ion conductors with high oxidation stability and shows great potential to high‐voltage ASSLIBs. [ABSTRACT FROM AUTHOR]

LiFePO4 has been widely used as a cathode material in lithium ion batteries. However, some impurity phases existing in LiFePO4 have a significant influence on its electrochemical performance. Therefore, detection of the impurity phases is necessary for the manufacturer in order to improve the quality of LiFePO4. In particular, visualization of the impurity and secondary phase distributions immersed in the bulk LiFePO4 crystal can help to understand the origin of the impurity and secondary phases, providing clear guidance towards the synthesis of high purity LiFePO4. The results show that with the combination of Raman and EDS, we are capable of identifying the low melting lithium phosphate phase in LFP ingot. Through micro XRF mapping, more detailed information about the LFP materials after carbon coating are observed. The secondary phases are easily defined due to the high sensitivity of this technology. [ABSTRACT FROM AUTHOR]

Lithium-rich layered material is one of the most promising candidates of cathode materials for next-generation electric vehicles. However, one of the major issues that pertains to this material is the oxygen release during initial charge, which results in low initial coulombic efficiency (CE), intense electrolyte oxidation and thermal instability. In this study, we have conducted aluminum phosphate (AlPO 4 ) coating via atomic layer deposition (ALD) approach to protect the surface of this cathode material powders. It was found that part of the C2/m Li 2 MnO 3 phase turned into a spinel-like phase during the ALD process. The oxygen release has been effectively suppressed by such transformation, the initial CE increased from 75.2% for the bare electrode to 86.2% for the electrode with only 5 ALD cycles of AlPO 4 coating. Furthermore, AlPO 4 was also found to be more effective in improving the thermal stability of the cathode material comparing to bare or Al 2 O 3 coated samples. Our study has provided a new possible solution towards cathode materials with high thermal resistance via conformal coating. [ABSTRACT FROM AUTHOR]

3D microbatteries hold great promise as on-board energy supply systems for microelectronic devices. The construction of 3D microbatteries relies on the development of film deposition techniques that can enable coatings of uniform electrode and electrolyte materials in high-aspect-ratio substrates. Here, a 3D FePO4 on carbon nanotubes (CNTs@FePO4) structure is fabricated by coating FePO4 on CNTs/carbon paper substrate using atomic layer deposition. Compared to FePO4 on a planar substrate, the 3D CNTs@FePO4 electrode exhibits significantly increased areal capacity and excellent rate capability for lithium-ion and sodium-ion storage. The 3D CNTs@FePO4 maintains areal capacities of 64 and 33 μAh cm−2 after 180 cycles for lithium-ion batteries (LIBs) and sodium-ion batteries, which are 16 and 33 times higher than those of planar FePO4 electrode, respectively. Moreover, hybrid 3D CNTs@FePO4@Li3PO4 structure is fabricated by coating Li3PO4 solid-state electrolyte on 3D CNTs@FePO4. The CNTs@FePO4@Li3PO4 electrode shows stable cycling performance in LIBs. Hard X-ray photoemission spectroscopy analysis demonstrates that the Li3PO4 coating prevents the formation of undesirable LiF in the solid-electrolyte interphase layer, which is believed to be responsible for the performance degradation in CNTs@FePO4. This work paves the way to building reliable 3D nanostructured electrode and electrolyte architectures for high areal capacity microbatteries. [ABSTRACT FROM AUTHOR]

Atomic layer deposition (ALD) is considered as a powerful technique to synthesize novel electrode materials for lithium-ion batteries (LIBs), because not only the compositions can be specifically designed to achieve higher battery performances, but also the materials can be deposited on various substrates for different purposes. Herein, a novel design of active material/electrolyte mixture electrode, i.e., titanium dioxide/lithium phosphate (TLPO) nanocomposite, has been successfully developed by ALD and deposited on carbon nanotube substrates (CNTs@TLPO) at 250 °C, by combining the ALD recipes of TiO2 and lithium phosphate (LPO). In the nanocomposite, TiO2 forms anatase nanocrystals, embedded in a matrix of amorphous lithium phosphate. CNTs@TLPO has been examined as an anode material for LIBs, exhibiting a similar electrochemical response as anatase TiO2 in the cyclic voltammetry testing. CNTs@TLPO presents an outstanding capacity of 204 mA h g−1 upon 200 cycles in charge and discharge cycling measurements, as well as a significantly improved rate capability compared with ALD deposited TiO2 on CNTs without LPO ALD cycles. This work shows that the in situ addition of solid-state electrolyte (e.g., lithium phosphate), which introduces higher Li+ ionic conductivity, is an efficient way to achieve high-performance electrode materials for LIBs by ALD. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium‐ion batteries (ASSLIBs) have gained substantial attention worldwide due to their intrinsic safety and high energy density. However, the large interfacial resistance of ASSLIBs, which originates from the interfacial reactions and inferior electrode–electrolyte contact between electrodes and solid electrolytes, dramatically constrains their electrochemical performance. Here a dual shell interfacial nanostructure is rationally designed to enable high‐performance ASSLIBs, in which the inner shell LiNbO3 suppresses the interfacial reactions while the outer shell Li10GeP2S12 enables intimate electrode–electrolyte contact. As a result, the dual shell structured Li10GeP2S12@LiNbO3@LiCoO2 exhibits a high initial specific capacity of 125.8 mAh g−1 (1.35 mAh cm−2) with an initial Coulombic efficiency of 90.4% at 0.1 C and 87.7 mAh g−1 at 1 C. More importantly, in situ X‐ray absorption near edge spectroscopy was performed for the first time to reveal the interfacial reactions between Li10GeP2S12 and LiCoO2. This dual shell nanostructure demonstrates an ideal interfacial configuration for realizing high‐performance ASSLIBs. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 conversion to formate is a promising approach for reducing CO2 level and obtaining value‐added chemicals, but its partial current density is still insufficient to meet the industrial demands. Herein, we developed a surface‐lithium‐doped tin (s‐SnLi) catalyst by controlled electrochemical lithiation. Density functional theory calculations indicated that the Li dopants introduced electron localization and lattice strains on the Sn surface, thus enhancing both activity and selectivity of the CO2 electroreduction to formate. The s‐SnLi electrocatalyst exhibited one of the best CO2‐to‐formate performances, with a partial current density of −1.0 A cm−2 for producing formate and a corresponding Faradaic efficiency of 92 %. Furthermore, Zn–CO2 batteries equipped with the s‐SnLi catalyst displayed one of the highest power densities of 1.24 mW cm−2 and an outstanding stability of >800 cycles. Our work suggests a promising approach to incorporate electron localization and lattice strain for the catalytic sites to achieve efficient CO2‐to‐formate electrosynthesis toward potential commercialization. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 conversion to formate is a promising approach for reducing CO2 level and obtaining value‐added chemicals, but its partial current density is still insufficient to meet the industrial demands. Herein, we developed a surface‐lithium‐doped tin (s‐SnLi) catalyst by controlled electrochemical lithiation. Density functional theory calculations indicated that the Li dopants introduced electron localization and lattice strains on the Sn surface, thus enhancing both activity and selectivity of the CO2 electroreduction to formate. The s‐SnLi electrocatalyst exhibited one of the best CO2‐to‐formate performances, with a partial current density of −1.0 A cm−2 for producing formate and a corresponding Faradaic efficiency of 92 %. Furthermore, Zn–CO2 batteries equipped with the s‐SnLi catalyst displayed one of the highest power densities of 1.24 mW cm−2 and an outstanding stability of >800 cycles. Our work suggests a promising approach to incorporate electron localization and lattice strain for the catalytic sites to achieve efficient CO2‐to‐formate electrosynthesis toward potential commercialization. [ABSTRACT FROM AUTHOR]

Olivine-type phosphates (LiMPO 4 , M = Fe, Mn, Co) are promising cathode materials for lithium-ion batteries that are generally accepted to follow first order equilibrium phase transformations. Herein, the phase transformation dynamics of sub-micro sized LiFePO 4 particles with limited rate capability at a low current density of 0.14 C was investigated. An in-situ X-ray Absorption Near Edge Structure (XANES) measurement was conducted at the Fe and P K-edge for the dynamic studies upon lithiation and delithiation. Fe K-edge XANES spectra demonstrate that not only lithium-rich intermediate phase Li x FePO 4 (x = 0.6–0.75), but also lithium-poor intermediate phase Li y FePO 4 (y = 0.1–0.25) exist during the charge and discharge, respectively. Furthermore, during charge and discharge, a fluctuation of the FePO 4 and LiFePO 4 fractions obtained by liner combination fitting around the imaginary phase fractions followed Faraday's law and the equilibrium first-order two-phase transformation versus reaction time is present, respectively. The charging and discharging process has a reversible phase transformation dynamics with symmetric structural evolution routes. P K-edge XANES spectra reveal an enrichment of PF 6 −1 anions at the surface of the electrode during charging. [ABSTRACT FROM AUTHOR]

A non-aqueous approach was developed to synthesize iron phosphate cathode materials by the atomic layer deposition (ALD) technique. Deposition of iron phosphate thin films was achieved on nitrogen-doped carbon nanotubes (NCNTs) by combining ALD subcycles of Fe 2 O 3 (ferrocene-ozone) and PO x (trimethyl phosphate-water) at 200 – 350 °C. The thickness of iron phosphate thin films depends linearly on the ALD cycle, indicating their self-limiting growth behavior. The growth per cycle of iron phosphate thin films was determined to be ∼ 0.2, 0.4, 0.6, and 0.5 Å, at 200, 250, 300, and 350 °C, respectively. Characterization by SEM, TEM, and HRTEM techniques revealed uniform and conformal coating of amorphous iron phosphates on the surface of NCNTs. XANES analysis confirmed Fe O P bonding in the iron phosphates prepared by ALD. Furthermore, electrochemical measurement verified the high electrochemical activity of the amorphous iron phosphate as a cathode material in lithium-ion batteries. It is expected that the amorphous iron phosphate prepared by this facile and cost-effective ALD approach will find applications in the next generation of lithium-ion batteries and thin film batteries as either cathode materials or surface coating materials. [ABSTRACT FROM AUTHOR]