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2 additive. It boosts conductivity, ensuring stability in LiTiN|LLZTO|LiTiN cells and high capacity in LFP full cells after long cycles, indicating potential for enhanced stability in lithium-metal batteries. [Display omitted] • TiN conversion addresses resistance challenges, boosting SSB performance. • TiN improves lithium-ion conductivity and reduces porosity in SSB structures. • Stable performance and high current density observed in LiTiN|LLZTO|LiTiN cells. • LFP full cells show high capacity and retention after 1000 cycles. • TiN promises enhanced cycle stability in lithium-metal batteries. Solid-state batteries (SSBs) represent a pivotal avenue of development owing to their superior energy density and enhanced safety profile. However, the widespread utilization about SSBs confronts challenges such as inadequate interfacial connectivity resulting in high resistance, dendrite formation, and volumetric fluctuations in the lithium metal anode during plating and stripping. In this study, we introduce an innovative and remarkably efficient approach, leveraging the transformative potential of TiN-induced conversion. This method yields a lithium-ion-conductive TiN material concurrently addressing pre-existing porosity. The LiTiN| LLZTO| LiTiN symmetric cell is particularly noteworthy for its remarkable long-term cycle stability, which exceeds 1000 h at 0.2 mA cm−2, and its remarkable critical current density of 1.4 mA cm−2 at 25 °C. By subjecting TiN, the formation of the Li-Ti-N phase is induced, thereby establishing an additional Li 3 N-conductive layer that significantly enhances battery performance. Of paramount significance is the validation of the exceptional attributes of the composite through the deployment of LiFePO 4 (LFP) full cells. In this configuration, the LFP coupled full cell manifests a remarkable discharge rate capacity of about 147 mAh g−1 at 1C, along with a noteworthy discharge capacity retention rate of 90 % even following 1000 charge and discharge cycles. These outcomes underscore the material's robust lithium affinity and uniform lithium-ion distribution, which together mitigate dendrite growth and enhance the cycle stability of lithium-metal batteries. [ABSTRACT FROM AUTHOR]

For the first time, we investigate the electrochemical stability of Cu and Al current collectors in PEO/LiTFSI polymer electrolyte. The Cu and Al foils are passivated up to 3 and 5 V, respectively; namely, CuO for Cu and double layers of AlF 3 on the Al 2 O 3 passive layer for the Al foil in contact with PEO/LiTFSI polymer electrolyte. [Display omitted] • In a solid-state polymer electrolyte, the passivation of Cu and Al current collectors remains completely. • Our discovery introduces stability of Cu and Al when in contact with PEO/LiTFSI polymer electrolyte. • A Cu-O layer remains stable as a passive layer on Cu metal up to 3.6 V. • Al surface passivates with double layers consisting of outer Al-F and inner Al-O up to 5 V. • This study suggests suitability of Cu and Al in contact with solid-state polymer electrolyte. Recent interest in solid-state lithium batteries prevails in the battery community because of their superiority in terms of safety concerns. Many works have been reported for electrodes and electrolytes and their suitability for solid-state polymer electrolytes to adopt in lithium batteries. Herein, for the first time, we report on the electrochemical stabilities of Cu and Al current collectors in a polyethylene oxide (PEO)-based solid-state electrolyte containing lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. Our work on the electrochemical dynamic- and transient-mode polarization of these electrodes indicates that Cu metal undergoes Cu–O passivation below 3 V. The adhered Cu-F layer on the CuO passive layer may be beneficial to delay undesired reaction such as corrosion. And it is further confirmed that Al metal passivates stably even up to 5 V; namely, the Al surface forms double layers of the outer Al–F and inner Al–O layers. These F- and O-based layers are attributed to the combination of the Al and O from the reductively decomposed PEO and further progress of Al 2 O 3 and HF (H+ + F− →HF), decomposed from the PEO (H+) and TFSI− (F−). Therefore, we verify that successful passivation on Cu and Al metal surfaces facilitates their suitability as current collectors for solid-state polymer lithium batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel high-performance composite solid polymer electrolyte is prepared. • The CSPE can effectively inhibit the dissolution and shuttle of organic cathode. • Solid Li-organic battery shows superior rate performance and ultralong lifespan. • The remarkable safety is achieved under high temperature and abuse conditions. Organic cathode materials have attracted widespread attention due to their diverse structures, abundant raw materials, low cost, and eco-friendliness. However, their practical applications are restricted because of the poor cycling stability and lifespan owing to the dissolution and shuttle effect of the organic cathode in the liquid electrolyte. In this work, a novel all-solid-state Li-organic battery with ultralong lifespan is developed by using perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) as the organic cathode, composite solid polymer electrolyte (hybrid polymer-LiTFSI-LLZTO, HLL) as the electrolyte, and Li metal as the anode. The as-prepared HLL electrolyte exhibits high ionic conductivity (1.46 × 10-4 S cm−1 at 30 °C), superior thermal stability (~202 °C), outstanding electrode/electrolyte interfacial compatibility, and significant suppression to the dissolution/shuttle of PTCDA and the growth of Li dendrite. Ascribing to these advantages, the solid-state PTCDA|HLL|Li battery delivers a reversible capacity of 60 mAh g−1 after 1000 cycles at a high current density of 500 mA g−1, corresponding to an outstanding capacity retention of 91%. Moreover, the solid-state PTCDA|Li battery presents an elevated thermal stable window (178 °C) and less heat release (430 J g−1) compared with the analogous battery using liquid electrolyte (151 °C and 486 J g−1). Furthermore, the solid-state battery exhibits desirable flexibility and satisfactory safety under various abuse conditions (bending, cutting, and punching), demonstrating its outstanding safety in practical environments. This work offers a new pathway toward safer, longer lifespan solid-state Li-organic batteries. [ABSTRACT FROM AUTHOR]

• Free-standing, flexible composite solid electrolytes are successfully prepared. • Composite electrolyte shows superior electrochemical, mechanical and thermal properties. • Solid LiFePO 4 |Li cell exhibits excellent cycling stability and rate performance. • Thermal safety of an entire solid Li battery was in-situ quantitative studied. The low room-temperature ionic conductivity, narrow voltage window, and poor thermal stability of solid polymer electrolyte hinder the application of high energy density, safer solid-state lithium batteries (SLBs). Hence, we developed a novel composite solid polymer electrolyte (CSPE) with high room-temperature ionic conductivity (2.4 × 10−4 S cm−1), wide voltage window (~4.8 V), and excellent thermal stability (~330 °C) by combining Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 ceramic filler with poly(vinylidene fluoride) (PVDF) polymer and bis(trifluoromethane)sulfonimide lithium (LiTFSI) salt. Free-standing, scalable, and mechanically robust CSPE separately coupled with LiFePO 4 and high-voltage LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathodes vs lithium anode demonstrated stable cycling. More importantly, we in-situ measured the thermal stable window (177 °C) with a small heat release (189 J g−1) during the thermal runaway of the entire CSPE coin cell. In contrast, the liquid electrolyte cell delivered a depressing thermal stable window (157 °C) and release a significant amount of heat (812 J g−1). The superior thermal safety of CSPE cell can be ascribed to the solid-state property and outstanding thermal stability of the CSPE. Most notably, this work not only proposes a promising CSPE but also highlights a reference for in-situ quantitative study on the thermal safety of entire SLBs. [ABSTRACT FROM AUTHOR]

• A homogeneous composite electrode is prepared through a liquid phase method. • LiG3 addition improves the electrochemical active interfaces within the composite electrode. • The SSLBs applying Li 4 Ti 5 O 12 active materials deliver superior rate capability and cycling performance. Solid-state lithium batteries (SSLBs) exhibit numerous advantages including high safety, high energy density and power density, etc., and therefore become the most promising candidate for next-generation batteries. However, constructing an intimate contact within the composite electrode and the electrode/electrolyte interface via simple mixing and cold-pressing processes is still challenging. Herein, a novel fabrication process for homogeneous composite electrodes used in SSLBs is successfully demonstrated. An in-situ liquid-phase approach employing the [Li(triglyme)]+[TFSI]- (LiG3) solvent-salt complex with excellent stability to modify the sulfide-based solid-state electrolyte interfaces, is introduced into the SSLBs system, which enables SSLBs to work efficiently at lower external pressures. The quasi-solid-state prototype cells with Li 4 Ti 5 O 12 (LTO) active material deliver excellent room-temperature performance, generating a super high capacity of 160 mA h g−1 and high capacity retention of 91.4% for 1500 cycles under 0.25 C. This work gives new insight into the interface engineering, processing and more positive impact on the industrial production of SSLBs. [ABSTRACT FROM AUTHOR]