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The challenge of safety problems in lithium batteries caused by conventional electrolytes at high temperatures is addressed in this study. A novel solid electrolyte (HKUST-1@IL-Li) was fabricated by immobilizing ionic liquid ([EMIM][TFSI]) in the nanopores of a HKUST-1 metal–organic framework. 3D angstrom-level ionic channels of the metal–organic framework (MOF) host were used to restrict electrolyte anions and acted as "highways" for fast Li+ transport. In addition, lower interfacial resistance between HKUST-1@IL-Li and electrodes was achieved by a wetted contact through open tunnels at the atomic scale. Excellent high thermal stability up to 300 °C and electrochemical properties are observed, including ionic conductivities and Li+ transference numbers of 0.68 × 10−4 S·cm−1 and 0.46, respectively, at 25 °C, and 6.85 × 10−4 S·cm−1 and 0.68, respectively, at 100 °C. A stable Li metal plating/stripping process was observed at 100 °C, suggesting an effectively suppressed growth of Li dendrites. The as-fabricated LiFePO4/HKUST-1@IL-Li/Li solid-state battery exhibits remarkable performance at high temperature with an initial discharge capacity of 144 mAh·g−1 at 0.5 C and a high capacity retention of 92% after 100 cycles. Thus, the solid electrolyte in this study demonstrates promising applicability in lithium metal batteries with high performance under extreme thermal environmental conditions. [ABSTRACT FROM AUTHOR]

• Novel 3D composite polymer electrolyte containing boron was successfully prepared. • B-CPE shows high t Na + and excellent electrochemical compatibility to Na anode. • The formed continuous polymer phase greatly facilitated charge-transfer. • Solid-state c-NFM/B-CPE/Na battery exhibits superior electrochemical performance. Practical application of solid-state batteries has been severely hindered by the relatively low ionic conductivity of electrolyte and high charge-transfer resistance between electrode and solid electrolyte. The development of novel materials and creation of new nanostructures are effective strategies to address the challenges. Here, an innovative 3D composite polymer electrolyte modified with anion-trapping boron (B-CPE) is reported for the first time as a solid electrolyte for sodium-ion batteries (SIBs). The B-CPE is prepared through in situ polymerization of polymer electrolyte inside a mechanically supporting matrix. It shows excellent ionic conductivity of 2.57 × 10−4 S cm−1 at 40 °C, high Na+ transference number of 0.66, and good interfacial compatibility with Na metal anode. Moreover, solid-state SIBs were assembled by one-step in situ solidification method to form "gentle" electrode/electrolyte contact, and it's found that the charge-transfer efficiency has been significantly improved at the electrode/electrolyte interface as well as in cathode due to the formation of ion-conducting continuous polymer phase. Hence the B-CPE based solid-state SIBs exhibit outstanding electrochemical performances as the synergistic effect of high performance electrolyte and optimized cell structure. It delivers initial discharge capacity of 113.8 mAh g−1 and maintains 80.1% of capacity during 320 cycles under 0.2 C at 40 °C, and even 80.4% of the capacity retention after 700 cycles under 3 C. Notably, the battery achieves a significant improvement in rate capability owing to the introduction of boron moieties. This work opens new possibilities to fabricate high performance other rechargeable solid-state batteries. [ABSTRACT FROM AUTHOR]

Solid-state batteries promise to meet the challenges of high energy density and high safety for future energy storage. However, poor interfacial contact and complex manufacturing processes limit their practical applications. Herein, a simple strategy is proposed to enhance interfacial contact by introducing a gradient composite polymer solid electrolyte (GCPE), which is prepared by a facile UV-curing polymerization technique. The high-Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO)-content side of the electrolyte exhibits high oxidation resistance (5.4 V versus Li + /Li), making it compatible with a high-voltage cathode material, whereas the LLZTO-deficient side achieves excellent interfacial contact with the Li metal anode, facilitating uniform Li deposition. Benefiting from the elaborate composition and structure of GCPE films, the symmetric Li//Li cell exhibits a low-voltage hysteresis potential of 42 mV and a long cycle life of >1900 h without short-circuiting. The Li//LiFePO 4 solid-state batteries deliver a capacity of 161.0 mA h g -1 at 60 °C and 0.1 C (82.4% capacity is retained after 200 cycles). Even at 80 °C, the cell still shows an outstanding capacity of 132.9 mAh g -1 at 0.2 C after 100 cycles. The design principle of gradient electrolytes provides a new path for achieving enhanced interfacial contact in high-performance solid-state batteries., (© 2021 Wiley-VCH GmbH.)

Lithium Batteries: Solvent-Free Synthesis of Thin, Flexible, Nonflammable Garnet-Based Composite Solid Electrolyte for All-Solid-State Lithium Batteries (Adv. Keywords: all-solid-state lithium batteries; composite solid electrolyte; flexible 3D garnet framework; solvent-free EN all-solid-state lithium batteries composite solid electrolyte flexible 3D garnet framework solvent-free 1 1 1 03/28/20 20200324 NES 200324 In article number 1903376, Li-Zhen Fan and co-workers prepare thin, flexible, and nonflammable composite solid electrolytes with plastic crystals in a 3D garnet-based framework by a facile, solvent-free method, and these unique composite solid electrolytes with high ionic conductivity and low interfacial resistance endow LiFePO SB 4 sb |Li and LiNi SB 0.5 sb Mln SB 0.3 sb Co SB 0.2 sb O SB 2 sb |Li cells with high discharge specific capacities, and desirable cyclic stabilities at room temperature. All-solid-state lithium batteries, composite solid electrolyte, flexible 3D garnet framework, solvent-free. [Extracted from the article]

• High performance PEO/Na 3 Zr 2 Si 2 PO 12 electrolyte films were prepared. • Na 3 Zr 2 Si 2 PO 12 based electrolytes possess excellent thermal stability. • Succinonitrile build better sodium ions transfer channels in cathode. • All-solid-state Na batteries exhibit excellent electrochemical performance. Solid electrolytes with satisfactory ionic conductivity, good flexibility, and ideal interface compatibility are the key to developing next-generation solid-state rechargeable sodium metal batteries. Herein, nano-sized NASICON-type Na 3 Zr 2 Si 2 PO 12 (NZSP) powders were firstly prepared by sol–gel method. After that, two kinds of high-performance polyethylene oxide/NZSP composite solid electrolytes were fabricated by solution-casting method, which exhibit high ionic conductivities (>10−4 S cm−1 at 55 °C), wide electrochemical window (>4.7 V vs. Na+/Na), and good capability to impede sodium dendrites. In order to build better transfer channels for sodium ions in cathode and relieve the volume change of cathode particles during cycling, succinonitrile interphase was introduced by a simple dispersing method. The all-solid-state Na 0.67 Ni 0.33 Mn 0.67 O 2 |Na batteries based on the two kinds of electrolytes both exhibit excellent electrochemical performances with high discharge capacity of 73.2 mA h g−1 (68.2 mA h g−1) and high capacity retention of 98.4% (97.6%) after 100 cycles at 0.5C and 55 °C. These results promise a splendid strategy for designing high performance all-solid-state sodium batteries. [ABSTRACT FROM AUTHOR]

A novel strategy has been proposed to produce in situ Li 2 S at the interfacial layer between lithium anode and the solid electrolyte, by using an amorphous-sulfide-LiTFSI-poly(vinylidene difluoride) (PVDF) composite solid electrolyte (SLCSE). Besides retarding the decomposition of PVDF in CSE, the Li 2 S-modified interfacial layer (SMIL) also improves the wettability between lithium metal and SLCSE which in turn optimizes the lithium deposition process. Our density functional theory calculation results reveal that the migration energy barrier of Li passing through SMIL is much lower than that of Li passing through LiF-modified interfacial layer (FMIL) formed from the decomposition of PVDF. The as-prepared SLCSE shows a Li ionic transference number of 0.44 and Li ion conductivity of 3.42 × 10 -4 S/cm at room temperature, and the Li||SLCSE||LiFePO 4 cell exhibits an outstanding rate performance with a capacity of 153, 144, 131, and 101 mAh/g at a current density of 0.05, 0.10, 0.25, and 0.50 mA/cm 2 , respectively.

Solid-state lithium batteries have attracted great attention owing to their potential advantages in safety and energy density. Among various solid electrolytes, solid polymer electrolyte is promising due to its good viscoelasticity, lightweight, and low-cost processing. However, key issues of solid polymer electrolyte include poor ionic conductivity and low Li + transference number, which limit its practical application. Herein, a new-type of ultraviolet cross-linked composite solid electrolyte (C-CSE), composed of ZIF-based ionic conductor (named ZIL) and polymer, is designed with enhanced ion transport. The ZIL is composed of ZIF-8 and ionic liquid, which can provide C-CSE with fast ion transport paths. Moreover, the proper pore size of ZIF-8 can restrict the migration of embedded ionic liquid and thus construct a solid-liquid transport interface between polymer chains and ZIF-8, which could achieve fast ion transport. In addition, ultraviolet irradiation can decrease the crystallization of C-CSE and thus increase the amorphous region. Consequently, the C-CSE show excellent electrochemical performance including high ionic conductivity of 0.426 mS cm -1 at 30 °C, high Li + transference number of 0.67, and good Li|Li compatibility cycle over 1040 h. Experimental and computational results indicate that diffusion energy barrier of Li + through ZIF-8 is smaller than that of polymer chains, which reveals a new Li + transport mechanism between polymer chains and ZIL, from "chain-chain-chain" to "chain-ZIL-chain". This work demonstrates rational design of ion transport paths at the interface of solid electrolyte could facilitate the development of solid-state lithium batteries as a promising novel strategy.

CsH2PO4 is a proton conductor pertaining to the acid salts group and shows a phase transition from monoclinic to cubic phase at 232 ± 2 °C under high-steam atmospheres (>30%). This cubic phase gives rise to the so-called superprotonic conductivity. In this work, the influence of the partial substitution of Cs by Ba and Rb, as well as the partial substitution of P by W, Mo, and S in CsH2PO4 on the phase transition temperature and electrochemical properties is studied. Among the tested materials, the partial substitution by Rb led to the highest conductivity at high temperature. Furthermore, Ba and S-substituted salts exhibited the highest conductivity at low temperatures. CsH2PO4 was used as electrolyte in a fully-assembled fuel cell demonstrating the applicability of the material at high pressures and the possibility to use other materials (Cu and ZnO) instead of Pt as electrode electrocatalyst. Finally, an electrolyzer cell composed of CsH2PO4 as electrolyte, Cu and ZnO as cathode and Pt and Ag as anode was evaluated, obtaining a stable production of H2 at 250 °C. [ABSTRACT FROM AUTHOR]

The formation of lithium dendrites is suppressed using a Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 -poly(ethylene oxide) (LAGP-PEO) composite solid electrolyte and a PEO (lithium bis(trifluoromethane)sulfonimide) [PEO (LiTFSI)]-modified lithium metal anode in all-solid-state lithium batteries. The effects on the anode performance based on the PEO content in the composite solid electrolyte and the molecular weight of PEO used to modify the Li anode are studied. The structure, surface morphology, and stability of the composite solid electrolyte are examined by X-ray diffraction spectroscopy, scanning electron microscopy, and electrochemical tests. Results show that the presence of a PEO-500000(LiTFSI) film on a Li anode results in good mechanical properties and satisfactory interface contact features. The film can also prevent Li from reacting with LAGP. Furthermore, the formation of lithium dendrites can be effectively inhibited as the composite solid electrolyte is combined with the PEO film on the Li anode. The ratio of PEO in the composite solid electrolyte can be reduced to a low level of 1 wt %. PEO remains stable even at a high potential of 5.12 V (vs Li/Li + ). The assembled Li-PEO (LiTFSI)/LAGP-PEO/LiMn 0.8 Fe 0.2 PO 4 all-solid-state cell can deliver an initial discharge capacity of 160.8 mAh g -1 and exhibit good cycling stability and rate performance at 50 °C.