Dual-Salt Electrolyte Additive Enables High Moisture Tolerance and Favorable Electric Double Layer for Lithium Metal Battery.

The carbonate electrolyte chemistry is a primary determinant for the development of high-voltage lithium metal batteries (LMBs). Unfortunately, their implementation is greatly plagued by sluggish electrode interfacial dynamics and insufficient electrolyte thermodynamic stability. Herein, lithium trifluoroacetate-lithium nitrate (LiTFA-LiNO3 ) dual-salt additive-reinforced carbonate electrolyte (LTFAN) is proposed for stabilizing high-voltage LMBs. We reveal that 1) the in situ generated inorganic-rich electrode-electrolyte interphase (EEI) enables rapid interfacial dynamics, 2) TFA- preferentially interacts with moisture over PF6 - to strengthen the moisture tolerance of designed electrolyte, and 3) NO3 - is found to be noticeably enriched at the cathode interface on charging, thus constructing Li+ -enriched, solvent-coordinated, thermodynamically favorable electric double layer (EDL). The superior moisture tolerance of LTFAN and the thermodynamically stable EDL constructed at cathode interface play a decisive role in upgrading the compatibility of carbonate electrolyte with high-voltage cathode. The LMBs with LTFAN realize 4.3 V-NCM523/4.4 V-NCM622 superior cycling reversibility and excellent rate capability, which is the leading level of documented records for carbonate electrode.

Cesium Cyclopropane Acid-Aided Crystal Growth Enables Efficient Inorganic Perovskite Solar Cells with a High Moisture Tolerance.

While all-inorganic halide perovskites (iHPs) are promising photovoltaic materials, the associated water sensitivity of iHPs calls for stringent humidity control to reach satisfactory photovoltaic efficiencies. Herein, we report a moisture-insensitive perovskite formation route under ambient air for CsPbI2 Br-based iHPs via cesium cyclopropane acids (C3 ) as a compound introducer. With this approach, appreciably enhanced crystallization quality and moisture tolerance of CsPbI2 Br are attained. The improvements are attributed to the modified evaporation enthalpy of the volatile side product of DMA-acid initiated by Cs-acids. As such, the water-involving reaction is directed toward the DMA-acids, leaving the target CsPbI2 Br perovskites insensitive to ambient humidity. We highlight that by controlling the C3 concentration, the dependence of power conversion efficiency (PCE) in CsPbI2 Br devices on the humidity level during perovskite film formation becomes favorably weakened, with the PCEs remaining relatively high (>15 %) associated with improved device stability for RH levels changed from 25 % to 65 %. The champion solar cells yield an impressive PCE exceeding 17 %, showing small degradations (<10 %) for 2000 hours of shell storage and 300 hours of 85/85 (temperature/humidity) tests. The demonstrated C3 -based strategy provides an enabler for improving the long-sought moisture-stability of iHPs toward high photovoltaic device performance.

Unleashing the Potential of High-Capacity Anodes through an Interfacial Prelithiation Strategy.

The scalable development of an environmentally adaptive and homogeneous Li+ supplementary route remains a formidable challenge for the existing prelithiation technologies, restricting the full potential of high-capacity anodes. In this study, we present a moisture-tolerant interfacial prelithiation approach through casting a hydrophobic poly(vinylidene-co-hexafluoropropylene) membrane blended with a deep-lithiated alloy (Li22Si5@C/PVDF-HFP) onto Si based anodes. This strategy could not only extend to various high-capacity anode systems (SiOx@C, hard carbon) but also align with industrial roll-to-roll assembly processes. By carefully adjusting the thickness of the prelithiation layer, the densely packed Si@C electrode (4.5 mAh cm-2) exhibits significantly improved initial Coulombic efficiency until a close-to-unit value, as well as extreme moisture tolerance (60% relative humidity). Furthermore, it achieves more than 10-fold enhancement of ionic conductivity across the electrode. As pairing the prelithiated Si@C anode with the LiNi0.8Co0.1Mn0.1O2 cathode, the 2 Ah pouch-format prototype balances an energy density of ∼371 Wh kg-1 and an extreme power output of 2450 W kg-1 as well as 83.8% capacity retention for 1000 cycles. The combined operando phase tracking and spatial arrangement analysis of the intermediate alloy elucidate that the enhanced Li utilization derives from the gradient stress dissipation model upon a spontaneous Li+ redistribution process.

Pseudohalide-induced moisture tolerance in perovskite CH3 NH3 Pb(SCN)2 I thin films.

Two pseudohalide thiocyanate ions (SCN(-) ) have been used to replace two iodides in CH3 NH3 PbI3 , and the resulting perovskite material was used as the active material in solar cells. In accelerated stability tests, the CH3 NH3 Pb(SCN)2 I perovskite films were shown to be superior to the conventional CH3 NH3 PbI3 films as no significant degradation was observed after the film had been exposed to air with a relative humidity of 95 % for over four hours, whereas CH3 NH3 PbI3 films degraded in less than 1.5 hours. Solar cells based on CH3 NH3 Pb(SCN)2 I thin films exhibited an efficiency of 8.3 %, which is comparable to that of CH3 NH3 PbI3 based cells fabricated in the same way.