Herein, it is proposed that poly(methylmethacrylate) (PMMA), a widely‐used thermoplastic in our daily life, can be used as an abundant, stable, and high‐performance anode material for rechargeable lithium‐ion batteries through a novel concept of lithium storage mechanism. The specially‐designed PMMA thin‐film electrode exhibits a high reversible capacity of 343 mA h g −1 at C/25 and maintains a capacity retention of 82.6% of that obtained at C/25 when cycled at 1 C rate. Meanwhile, this pristine PMMA electrode without binder and conductive agents shows a high reversible capacity of 196.8 mA h g −1 after 150 cycles at 0.2 C with a capacity retention of 73.5%. Additionally, PMMA‐based binder is found to enhance both the reversible capacity and rate capability of the graphite electrodes. Hence, this new type of organic electrode material may have a great opportunity to be utilized as the active material or rechargeable binder in flexible or transparent thin‐film batteries and all‐solid batteries. The present work also provides a new way of seeking more proper organic electrode materials which don't contain conjugated structures and atoms with lone pair electrons required in traditional organic electrode materials.
Abstract Smart integration of transition‐metal sulfides/oxides/nitrides with the conductive MXene to form hybrid materials is very promising in the development of high‐performance anodes for next‐generation Li‐ion batteries (LIBs) owing to their advantages of high specific capacity, favorable Li + intercalation structure, and superior conductivity. Herein, a facile route was proposed to prepare strongly coupled MoS 2 nanocrystal/Ti 3 C 2 nanosheet hybrids through freeze‐drying combined with a subsequent thermal process. The Ti 3 C 2 host could enhance the reaction kinetics and buffer the volume change of MoS 2 at a low content (8.87 wt %). Thus, the MoS 2 /Ti 3 C 2 hybrids could deliver high rate performance and excellent cycling durability. As such, high reversible capacities of 835.1 and 706.0 mAh g −1 could be maintained after 110 cycles at 0.5 A g −1 and 1390 cycles at 5 A g −1 , respectively, as well as an outstanding rate capability with a capacity retention over 65.8 % at 5 A g −1 . This synthetic strategy could be easily extended to synthesize other high‐performance MXene‐supported hybrid electrode materials.
Graphene is readily p-doped by adsorbates, but for device applications, it would be useful to access the n-doped material. Individual graphene nanoribbons were covalently functionalized by nitrogen species through high-power electrical joule heating in ammonia gas, leading to n-type electronic doping consistent with theory. The formation of the carbon-nitrogen bond should occur mostly at the edges of graphene where chemical reactivity is high. X-ray photoelectron spectroscopy and nanometer-scale secondary ion mass spectroscopy confirm the carbon-nitrogen species in graphene thermally annealed in ammonia. We fabricated an n-type graphene field-effect transistor that operates at room temperature.
Abstract Large interfacial resistance resulting from interfacial reactions is widely acknowledged as one of the main challenges in sulfide electrolytes (SEs)‐based all‐solid‐state lithium batteries (ASSLBs). However, the root cause of the large interfacial resistance between the SEs and typical layered oxide cathodes is not fully understood yet. Here, it is shown that interfacial oxygen loss from single‐crystal LiNi 0.5 Mn 0.3 Co 0.2 O 2 (SC‐NMC532) chemically oxidizes Li 10 GeP 2 S 12 , generating oxygen‐containing interfacial species. Meanwhile, the interfacial oxygen loss also induces a structural change of oxide cathodes (layered‐to‐rock salt). In addition, the high operation voltage can electrochemically oxidize SEs to form non‐oxygen species (e.g., polysulfides). These chemically and electrochemically oxidized species, together with the interfacial structural change, are responsible for the large interfacial resistance at the cathode interface. More importantly, the widely adopted interfacial coating strategy is effective in suppressing chemically oxidized oxygen‐containing species and mitigating the coincident interfacial structural change but is unable to prevent electrochemically induced non‐oxygen species. These findings provide a deeper insight into the large interfacial resistance between the typical SE and layered oxide cathodes, which may be of assistance for the rational interface design of SE‐based ASSLBs in the future.
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