Qiang Zhang,Xiayin Yao,Jean Pierre Mwizerwa,Ning Huang,Hongli Wan,Zhen Huang,Xiaoxiong Xu
Transition metal sulfides have attracted particular interests owing to their extremely higher specific capacity and more compatible with sulfide electrolyte than lithium transition-metal oxide for all-solid-state lithium batteries. FeS nanosheets with thickness of 10 nm are synthesized by a poly (vinyl alcohol)-assisted precipitation method and further successfully employed in Li/70%Li 2 S-29%P 2 S 5 –1%P 2 O 5 /Li 10 GeP 2 S 12 /FeS all-solid-state lithium batteries. The obtained all-solid-state lithium batteries show reversible discharge capacity of 550 mAh g − 1 after 50 cycles at current density of 0.1 A g − 1 and exhibit superior rate performances.
Sulfide-based all-solid-state lithium-ion batteries (ASSLIBs) are promising candidates in the next generation of energy storage technology; the voltage mismatch and the resulting side reactions at the interface between the cathode and the solid electrolyte, however, dramatically deteriorate their cycling performance. Herein, for the first time, we report that the chemical interaction between LiCoO2 (LCO) and TiO2 can be regulated by two additives, carbon and Li2CO3, which in situ form a continuous ultrathin pure-phase Li2CoTi3O8 (LCTO) layer with a stable 3D network of spinel structures, relatively low electronic conductivity (2.5 × 10−8 S cm−1) and high lithium diffusion coefficient (DLi+ = 8.22 × 10−7 cm2 s−1) on the surface of LCO. When assembled in ASSLIBs, such an LCTO layer functions as an interlayer between the LCO and the Li10GeP2S12 solid electrolyte (LGPS). As a consequence, the original interface LCO/LGPS is substituted by two new interfaces LCO/LCTO and LCTO/LGPS. DFT calculations indicate that, compared with the LCO/LGPS, the new interfaces are not only thermodynamically and electrochemically more compatible, but also have higher interfacial affinity. Therefore, the relevant ASSLIB exhibits evidently reduced interfacial impedance, and it also displays a high initial capacity of 140 mA h g−1 and a reversible discharge specific capacity of 116 mA h g−1 after 200 cycles at room temperature (0.1C). In comparison, the ASSLIB assembled without the LCTO interlayer delivers an initial capacity of 98 mA h g−1 and only retains 22.4% capacity after 100 cycles (0.1C). Even at a high cutoff voltage (4.5 V vs. Li/Li+), the ASSLIB with the LCTO interlayer could also exhibit a high initial capacity of 180 mA h g−1 and a remarkable retention of 132 mA h g−1 after 100 cycles.
Zi Xin Huang,Ting Zhang,Ze Ping Zhang,Min Zhi Rong,Ming Qiu Zhang
Ceramic–polymer composite solid electrolytes (CSEs) have attracted great attention by combining the advantages of polymer electrolytes and inorganic ceramic electrolytes. Herein, Li10GeP2S12 (LGPS) particles are incorporated into poly(ethylene oxide) (PEO)-based reversibly interlocked polymer networks (RILNs) derived from the topological rearrangement of two PEO networks cross-linked by reversible imine bonds and disulfide linkages. A series of highly ionic conductive, self-healing CSEs are obtained accordingly. The interlocking architecture successfully inhibits PEO crystallization, increasing the amorphous phase for Li ion transportation, and stabilizes the conductive pathways of LGPS particles by its unique confinement effect. Meanwhile, the LGPS particles cooperate with the RILN matrix, forming a filler–polymer interfacial phase for additional Li ion transportation and strengthening and toughening the resultant CSEs via the strong intermolecular Li+–O2– interactions. Furthermore, the dynamic characteristics of the included reversible bonds ensure a multiple intrinsic self-healing capability. Consequently, the CSEs containing 15 wt % LGPS deliver a high ionic conductivity (1.06 × 10–3 S cm–1) and high Li ion transference number (∼0.6) at 25 °C, a wide electrochemical stability window (>4.9 V), good mechanical properties (0.63 MPa, 377%), and a stable CSE/Li anode interface. The integrated Li/CSE/LiFePO4 battery exhibits a specific discharge capacity of 110.8 mAh g–1 at 1 C (25 °C) and a capacity retention of 76.9% after 200 cycles. Thanks to the healability, the damaged CSEs can regain the structural integrity, ion conductive capability, and cycling performance of the assembled cells. The present work provides an effective strategy to fabricate CSEs for lithium metal batteries that are workable at ambient temperature.
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