Negatively Charged Laponite Sheets Enhanced Solid Polymer Electrolytes for Long-Cycling Lithium-Metal Batteries

Vertically-Aligned Card-House Structure for Composite Solid Polymer Electrolyte with Fast and Stable Ion Transport Channels

All-solid-state lithium batteries (ASSLBs) are highly promising as next-generation energy storage devices owing to their potential for great safety and high energy density. This work demonstrates that composite solid polymer electrolyte with vertically-aligned card-house structure can simultaneously improve the high rate and long-term cycling performance of ASSLBs. The vertical alignment of laponite nanosheets creates fast and uniform Li+ ion transport channels at the nanosheets/polymer interphase, resulting in high ionic conductivity of 8.9 × 10-4 S cm-1 and Li+ transference number of 0.32 at 60 °C, as well as uniformly distributed solid electrolyte interphase. Such electrolyte is characterized by high mechanical strength, low flammability, excellent structural stability and stable ion transport channels. In addition, the ASSLB cell with the electrolyte and LiFePO4 cathode delivers a high discharge specific capacity of 124.8 mAh g-1, which accounts for 85.6% of its initial capacity after 500 cycles at 1C. The reasonable design through structural control strategy by interconnecting the vertically-aligned nanosheets open a way to fabricate high performance composite solid polymer electrolytes.

Phenylboronic Acid Functionalized Calix[4]pyrrole-Based Solid-State Supramolecular Electrolyte

Solid-state polymer electrolytes (SPEs) suffer from the low ionic conductivity and poor capability of suppressing lithium (Li) dendrites, which limits their utility in the preparation of all solid-state Li-metal batteries (LMBs). It is reported here a flexible solid supramolecular electrolyte that incorporates a new anion capture agent, namely a phenylboronic acid functionalized calix[4]pyrrole (C4P), into a poly(ethylene oxide) (PEO) matrix. The resulting solid-state supramolecular electrolyte demonstrates high ionic conductivity (1.9 × 10-3  S cm-1 at 60 °C) and a high Li+ transference number (t Li + ${t}_{{\mathrm{Li}}^{\mathrm{ + }}}$  = 0.70). Furthermore, the assembled Li|C4P-PEO-LiTFSI|LiFePO4 cell allows for stable cycling over 1200 cycles at 1 C at 60 °C, as well as good rate performance. The favorable performance of the C4P-PEO-LiTFSI SPE leads to suggest it can prove useful in the creation of high energy density solid-state LMBs.

LLZTO Nanoparticle- and Cellulose Mesh-Coreinforced Flexible Composite Electrolyte for Stable Li Metal Batteries

Composite electrolytes have been regarded as the most prospective electrolytes for commercial application because they acquire the advantages of both polymer and inorganic electrolytes, commonly exhibiting appreciated flexibility and suitable ionic conductivity. Nevertheless, the conventional solution-casting method with toxic solvent and poor interfacial contact still hamper their commercialization process. Moreover, electrolytes with higher ionic conductivity and transference number are urgently needed for satisfying fast-charging batteries. Herein, a novel composite electrolyte (LZEC) reinforced by mechanically robust LLZTO nanoparticles and flexible cellulose mesh was fabricated by a simple and advanced in situ thermal polymerization method, with adding of highly ion-conductive liquid plasticizer. Consequently, the rationally designed LZEC composite electrolyte exhibits superior flexibility and remarkable electrochemical properties in the form of high ionic conductivity, wide electrochemical stability window, and high Li+ transference number. Importantly, the in situ synthesis method is expected to help construct an enhanced electrolyte/electrode interface inside the battery, and the LZEC composite electrolyte is capable of suppressing Li dendrite growth effectively, as evidenced by the prolonged stable cycling of the Li/Li symmetric cell. Therefore, the LFP/LZEC/Li full cell exhibits superior rate performance and long cyclic life. These attractive properties make LZEC a potential composite electrolyte for boosting the practical application of safe and long-life Li metal batteries.

Laponite-Supported Gel Polymer Electrolyte with Multiple Lithium-Ion Transport Channels for Stable Lithium Metal Batteries

Lithium metal batteries have emerged as a promising candidate for next-generation power systems. However, the high reactivity of lithium metal with liquid electrolytes has resulted in decreased battery safety and stability, which poses a significant challenge. Herein, we present a modified laponite-supported gel polymer electrolyte (LAP@PDOL GPE) that was fabricated using in situ polymerization initiated by a redox-initiating system at ambient temperature. The LAP@PDOL GPE effectively facilitates the dissociation of lithium salts via electrostatic interaction and simultaneously constructs multiple lithium-ion transport channels within the gel polymer network. This hierarchical GPE demonstrates a remarkable ionic conductivity of 5.16 × 10^-4 S cm^-1 at 30 °C. Furthermore, the robust laponite component of the LAP@PDOL GPE forms a barrier against Li dendrite growth while also participating in the establishment of a stable electrode/electrolyte interface with Si-rich components. The in situ polymerization process further improves the interfacial contact, enabling the LiFePO₄/LAP@PDOL GPE/Li cell to exhibit an impressive capacity of 137 mAh g^-1 at 1C, with a capacity retention of 98.5% even after 400 cycles. In summary, the developed LAP@PDOL GPE shows great potential in addressing the critical issues of safety and stability associated with lithium metal batteries while also delivering improved electrochemical performance.