Engineering heterogeneous composite electrodes consisting of multiple active components for meeting various electrochemical and structural demands have proven indispensable for significantly boosting the performance of lithium‐ion batteries (LIBs). Here, a novel design of ZnS/Sn heterostructures with rich phase boundaries concurrently encapsulated into hierarchical interconnected porous nitrogen‐doped carbon frameworks (ZnS/Sn@NPC) working as superior anode for LIBs, is showcased. These ZnS/Sn@NPC heterostructures with abundant heterointerfaces, a unique interconnected porous architecture, as well as a highly conductive N‐doped C matrix can provide plentiful Li+‐storage active sites, facilitate charge transfer, and reinforce the structural stability. Accordingly, the as‐fabricated ZnS/Sn@NPC anode for LIBs has achieved a high reversible capacity (769 mAh g−1, 150 cycles at 0.1 A g−1), high‐rate capability and long cycling stability (600 cycles, 645.3 mAh g−1 at 1 A g−1, 92.3% capacity retention). By integrating in situ/ex situ microscopic and spectroscopic characterizations with theoretical simulations, a multiscale and in‐depth fundamental understanding of underlying reaction mechanisms and origins of enhanced performance of ZnS/Sn@NPC is explicitly elucidated. Furthermore, a full cell assembled with prelithiated ZnS/Sn@NPC anode and LiFePO4 cathode displays superior rate and cycling performance. This work highlights the significance of chemical heterointerface engineering in rationally designing high‐performance electrodes for LIBs.
Despite the high specific capacity of silicon as a promising anode material for the next-generation high-capacity Li-ion batteries (LIBs), its practical applications are impeded by the rapid capacity decay during cycling. To tackle the issue, herein, a bindergrafting strategy is proposed to construct a covalently cross-linked binder [carboxymethyl cellulose/phytic acid (CMC/PA)], which builds a robust branched network with more contact points, allowing stronger bonds with Si nanoparticles by hydrogen bonding. Benefitting from the enhanced mechanical reliability, the resulting Si-CMC/PA electrodes exhibit a high reversible capacity with improved long-term cycling stability. Moreover, an assembled full cell consisting of the as-obtained Si-CMC/PA anode and commercial LiFePO 4 cathode also exhibits excellent cycling performance (120.4 mA h g −1 at 1 C for over 100 cycles with 88.4% capacity retention). In situ transmission electron microscopy was employed to visualize the binding effect of CMC/PA, which, unlike the conventional CMC binder, can effectively prevent the lithiated Si anodes from cracking. Furthermore, the combined ex situ microscopy and X-ray photoelectron spectroscopy analysis unveils the origin of the superior Li-ion storage performance of the Si-CMC/PA electrode, which arises from its excellent structural integrity and the stabilized solid−electrolyte interphase films during cycling. This work presents a facile and efficient binder-engineering strategy for significantly improving the performance of Si anodes for next-generation LIBs.
Lithium (Li) metal batteries with high energy density
are of great
promise for next-generation energy storage; however, they suffer from
severe Li dendritic growth and an unstable solid electrolyte interphase.
In this study, a mixed ionic and electronic conductive (MIEC) interphase
layer with an adjustable ratio assembled by ZnO and Zn nanoparticles
is developed. During the initial cycle, the in situ formed Li2O with high ionic conductivity and a lithiophilic
LiZn alloy with high electronic conductivity enable fast Li+ transportation in the interlayer and charge transfer at the ion/electron
conductive junction, respectively. The optimized interface kinetics
is achieved by balancing the ion migration and charge transfer in
the MIEC Li2O–LiZn interphase. As a result, the
symmetric cell with MIEC interphase delivers superior cycling stability
of over 1200 h. Also, Li||Zn-ZnO@PP||LFP (LFP = LiFePO4) full cells exhibit long cyclic life for 2000 cycles with a very
high capacity retention of 91.5% at a high rate of 5 C and stable
cycling for 350 cycles at a high LFP loading mass of 13.27 mg cm–2.
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