A novel strategy to improve the electrochemical properties of in-situ polymerized 1,3-dioxolane electrolyte in lithium metal batteries.

The application of solid-state electrolytes (SSEs) is anticipated to enhance the safety performance of lithium metal batteries (LMBs). However, the progress of SSEs has been hindered by the unstable electrode-electrolyte interfaces (EEIs). In this study, in-situ polymerization of 1,3-dioxolane (DOL) is employed for the preparation of SSEs, with the addition of tributyl borate (TBB) to establish stable EEIs, particularly under high-voltage conditions. On one hand, the addition of TBB promotes the dissociation of lithium salts and increases the concentration of free Li+, resulting in an increase in room temperature ionic conductivity to 1.13 × 10-4 S cm-1 and an improvement in the Li+ transference number to 0.69 for the prepared poly-DOL electrolytes (PDE-TBB). Benefiting from the enhanced Li+ transport, the Li/PDE-TBB/Li symmetric cell exhibits a cycle life exceeding 1,000 h with a low polarization voltage as low as 12 mV, and the Li/PDE-TBB/LiFePO4 cell demonstrates exceptional cyclic stability over 800 cycles at 1C, with a coulombic efficiency exceeding 99.8 % and a capacity retention of 89.6 %. On the other hand, PDE-TBB exhibits improved stability under high-voltage conditions and the capacity to establish robust boron-rich cathode electrolyte interphase (CEI) on the LiNi0.8Co0.1Mn0.1O2 (NCM811) surface, thereby enhancing the structural stability of cathode materials and ensuring exceptional cycling performance of Li/PDE-TBB/NCM811cell. This work presents a promising strategy for developing novel ether-based SSEs suitable for high-voltage lithium metal batteries.

Xi K ，Wang Y ，Li C ，Lei Y ，Xu X ，Wei L ，Gao Y ... -  《-》

In Situ Electrochemical Polymerization of Cathode Electrolyte Interphase Enabling High-Performance Lithium Metal Batteries.

Lithium metal batteries (LMBs) with high-voltage nickel-rich cathodes show great potential as energy storage devices due to their exceptional capacity and power density. However, the detrimental parasitic side reactions at the cathode electrolyte interface result in rapid capacity decay. Herein, a polymerizable electrolyte additive, pyrrole-1-propionic acid (PA), which can be in situ electrochemically polymerized on the cathode surface and involved in forming cathode electrolyte interphase (CEI) film during cycling is proposed. The formed CEI film prevents the formation of microcracks in LiNi0.8Co0.1Mn0.1O2 (NCM811) secondary particles and mitigates parasitic reactions. Additionally, the COO- anions of PA promote the acceleration of Li+ transport from cathode particles and increase charging rates. The Li||NCM811 batteries with PA in the electrolyte exhibit a high capacity retention of 83.83% after 200 cycles at 4.3 V, and maintain 80.88% capacity after 150 cycles at 4.6 V. This work provides an effective strategy for enhancing interface stability of high-voltage nickel-rich cathodes by forming stable CEI film.

Sun S ，Yu J ，Ma X ，Fang P ，Yang M ，Yang J ，Wu M ，Hu Y ，Yan F ... -  《-》

In Situ-Initiated Poly-1,3-dioxolane Gel Electrolyte for High-Voltage Lithium Metal Batteries.

Xin M ，Zhang Y ，Liu Z ，Zhang Y ，Zhai Y ，Xie H ，Liu Y ... -  《MOLECULES》

In Situ Formed Gel Polymer Electrolytes Enable Stable Solid Electrolyte Interface for High-Performance Lithium Metal Batteries.

Hao Q ，Yan J ，Gao Y ，Chen F ，Chen X ，Qi Y ，Li N ... -  《-》

LiF/Li(3)N-Rich Electrode-Electrolyte Interfaces Enabled by Multi-Functional Electrolyte Additive to Achieve High-Performance Li/LiNi(0.8)Co(0.1)Mn(0.1)O(2) Batteries.

LiPF6-based carbonate electrolytes have been extensively employed in commercial Li-ion batteries, but they face numerous interfacial stability challenges while applicating in high-energy-density lithium-metal batteries (LMBs). Herein, this work proposes N-succinimidyl trifluoroacetate (NST) as a multifunctional electrolyte additive to address these challenges. NST additive could optimize Li+ solvation structure and eliminate HF/H2O in the electrolyte, and preferentially be decomposed on the Ni-rich cathode (LiNi0.8Co0.1Mn0.1O2, NCM811) to generate LiF/Li3N-rich cathode-electrolyte interphase (CEI) with high conductivity. The synergistic effect reduces the electrolyte decomposition and inhibits the transition metal (TM) dissolution. Meanwhile, NST promotes the creation of solid electrolyte interphase (SEI) rich in inorganics on the Li metal anode (LMA), which restrains the growth of Li dendrites, minimizes parasitic reactions, and fosters rapid Li+ transport. As a result, compared with the reference, the Li/LiNi0.8Co0.1Mn0.1O2 cell with 1.0 wt.% NST exhibits higher capacity retention after 200 cycles at 1C (86.4% vs. 64.8%) and better rate performance, even at 9C. In the presence of NST, the Li/Li symmetrical cell shows a super-stable cyclic performance beyond 500 h at 0.5 mA cm-2/0.5 mAh cm-2. These unique features of NST are a promising solution for addressing the interfacial deterioration issue of high-capacity Ni-rich cathodes paired with LMA.

Lei Y ，Xu X ，Yin J ，Xi K ，Wei L ，Zheng J ，Wang Y ，Wu H ，Jiang S ，Gao Y ... -  《-》