Luyi Yang

A Metal–Organic‐Framework‐Based Electrolyte with Nanowetted Interfaces for High‐Energy‐Density Solid‐State Lithium Battery

Solid-state batteries (SSBs) are promising for safer energy storage, but their active loading and energy density have been limited by large interfacial impedance caused by the poor Li+ transport kinetics between the solid-state electrolyte and the electrode materials. To address the interfacial issue and achieve higher energy density, herein, a novel solid-like electrolyte (SLE) based on ionic-liquid-impregnated metal-organic framework nanocrystals (Li-IL@MOF) is reported, which demonstrates excellent electrochemical properties, including a high room-temperature ionic conductivity of 3.0 × 10-4 S cm-1 , an improved Li+ transference number of 0.36, and good compatibilities against both Li metal and active electrodes with low interfacial resistances. The Li-IL@MOF SLE is further integrated into a rechargeable Li|LiFePO4 SSB with an unprecedented active loading of 25 mg cm-2 , and the battery exhibits remarkable performance over a wide temperature range from -20 up to 150 °C. Besides the intrinsically high ionic conductivity of Li-IL@MOF, the unique interfacial contact between the SLE and the active electrodes owing to an interfacial wettability effect of the nanoconfined Li-IL guests, which creates an effective 3D Li+ conductive network throughout the whole battery, is considered to be the key factor for the excellent performance of the SSB.

Ordered mesoporous silica framework based electrolyte with nanowetted interfaces for solid-state lithium batteries

The practical applications of lithium metal as an anode material are hindered by the uncontrollable growth of lithium dendrites. Herein, an ordered mesoporous silica framework (MCM-41) based solid-state electrolyte (Li-IL@MCM-41 SSE) with nanoconfined ionic liquids is prepared through a post-impregnation method. The as-prepared electrolyte with nanowetted interfaces demonstrates suppression towards lithium dendrites, high thermal stability (up to 350 °C) and excellent electrochemical properties, such as high ionic conductivity (3.98 × 10−4 S cm−1 at 30 °C), a broad electrochemical potential window (up to 5.2 V) and good compatibility with different electroactive materials. The solid-state batteries (SSBs) assembled exhibited excellent cycling performance, delivering capacities of 138 mA h g−1, 127 mA h g−1 and 163 mA h g−1 after 100 cycles at room temperature with LiFePO4, LiCoO2, and LiNi0.8Co0.1Mn0.1O2 cathode materials, respectively. The good battery performance can be ascribed to the effective three-dimensional ion-conducting networks established by the nanowetted interfaces. The aforementioned results exhibit the good prospects of the Li-IL@MCM-41 SSE for application in lithium metal batteries.

A Conductive Binder for High-Performance Sn Electrodes in Lithium-Ion Batteries

Tin (Sn) has been widely studied as a promising anode material for high-energy and high-power-density Li-ion batteries owing to its high specific capacity. In this work, a water-soluble conductive polymer is studied as a binder for nanosized Sn anodes. Unlike conventional binders, this conductive polymer formed a conductive network, which maintained the mechanical integrity during the repeated charge and discharge processes despite the inevitable Sn particle pulverization. The resultant Sn anode without conductive additives showed a specific capacity of 593 mA h g-1 after 600 cycles at the current density of 500 mA g-1, exhibiting better cycling stability as well as rate performance compared to Sn anodes with conventional binders. Furthermore, it was also found that the conductive binder enhanced the formation of stable solid electrolyte interphase (SEI) layers.

Conductive Binder for Si Anode with Boosted Charge Transfer Capability via n-Type Doping

Employing conductive binders in silicon (Si) anode has been considered as a fundamental solution to the pulverization of Si particles. Therefore, it is still a great challenge to improve the charge transfer capability of the conductive binder. Herein, a copolymer (PFPQ-COONa) is synthesized, characterized, and electrochemically tested as conductive binder for Si anode. It is found that PFPQ-COONa exhibits not only excellent cycling stability, but also satisfactory rate performance with relatively high areal loading, which outperforms currently reported single-component conductive binders. The superior electrochemical performance can be attributed to the molecular-level contact between binder and Si particles and to the enhanced intrinsic conductivity of PFPQ-COONa at reductive potential. This method provides a fresh perspective to design and develop conductive binder for high-capacity battery anode.