Interfacial Modifications Of Electrodes In Lithium-Ion Batteries

Lithium-ion batteries are most dominant among other type of batteries due to better power and energy density,long cycle life,slow self-discharge rate,light weight,high operation voltage,and so on.Therefore,uses of lithium-ion batteries are rapidly increasing with growth of portable electronics and electric vehicles market.On the other hand,the world is becoming to rely on renewable energy more and more due to fossil fuel shortage and serious climate changes.Lithium-ion batteries can be considered as one of the principal solutions.Their performance is highly dependent on the interfacial properties of electrodes.In fact,there are several possible ways to develop green,ecofriendly,safer,and economical batteries such as use of cobalt-free cathode materials,water-based electrode fabrication,use of highly abundance and cheap materials,and improve performance of recently used materials by effective strategies.All these issues must involve designing the facile and stable interfaces of electrode materials in more practicable lithium-ion batteries and the strategies of interfacial modifications are summarized as follows,[1]LiNi0.5Mn1.5O4LNMO)is one of attractive cathode material due to its higher operational voltage(～4.7V),excellent performance at higher charge/discharge rates,price and eco-friendliness.However,detrimental interfacial side reactions,inducing electrolyte decomposition and transition metal dissolution hindering from its practical applications.To overcome this issue,herein,coated a thin polyphenyl film onto the surface of LNMO via the spontaneous dediazonation of C6H5N2+BF4-at roomtemperature.This conductive film facilitates fast Li ion diffusion,and reinforces the compatibility of LNMO against electrolyte by efficiently suppressing the electrolyte decomposition catalysed by LNMO while reducing transition metal dissolution.[2]Commercially available white latex(WL),containing polyvinyl acetate as staple ingredient,was directly used as an alternative aqueous binder for polyvinylidene fluoride(PVdF)in fabrication of graphite and Li4Ti5O12-based lithium-ion anodes.WL exhibits robust adhesion of electrode coating to current collector,meanwhile,the restricted electrolyte swelling of binder.Outperforming to PVdF,WL endows graphite with extensive surface coverage by binding agent,dramatically reducing irreversible decomposition of electrolyte(SEI formation)on graphite.Consequently,the WL-based graphite anode delivers the highest initial coulombic efficiency(CE)of 92%and remarkable long cyclic stability with high-capacity retention,as compared with common binders.Moreover,WL is also compatible with Li4Ti5O12,rendering it with more stable cycling behavior.[3]The novel water-based composite was proposed in the fabrication of cathode of layered transitional oxides,LiNi0.5Co0.2Mn0.3O2(NCM 523).This economical,ecofriendly and scalable approach which is featured with CMC,WL,acetylene black,and NCM 523 aiming towards green and sustainable lithium-ion batteries.This novel composite possess the interface which facilitates fast Li+transport while minimizing transition metal dissolution and enhancing compatibility of electrode-electrolyte interface.Then the full cell was constructed using both anode and cathode fabricated by the aqueous binder,which feature will be beneficial for the sustainability of lithiumion batteries.