Mixed ion-electron conducting Li_(3)P for efficient cathode prelithiation of all-solid-state Li-ion batteries

All-solid-state batteries(ASSBs)using sulfide electrolytes hold promise for next-generation battery technology.Although using a pure Li metal anode is believed to maximize battery energy density,numerous recent studies have implicated that Li-ion anodes(e.g.,graphite and Si)are more realistic candidates due to their interfacial compatibility with sulfide electrolytes.However,those Li-ion ASSBs suffer from an issue similar to liquid Li-ion batteries,which is a loss of active Li inventory owing to interfacial side reactions between electrode components,resulting in reduced available capacities and shortened cycle life.Herein,for the first time,we explore the potential of Li_(3)P for cathode prelithiation of Li-ion ASSBs.We identify that the crystallized Li_(3)P(c-Li_(3)P)has room-temperature ionic and electronic conductivities of both over 1o-4 s/cm.Such a mixed ion-electron conduct-ing feature ensures that the neat c-LisP affords a high Li+-releasing capacity of 983 mAh/g in ASSBs during the first charging.Moreover,the electro-chemical delithiation of c-LisP takes place below 2 V versus Li+/Li,while its lithiation dominates below 1 V versus Lit/Li.Once used as a cathode prelithiation regent for ASSBs,c-Li_(3)P only functions as a Li+donor without lithiation activity and can adequately compensate for the Li loss with minimal dosage added.Besides mitigating first-cycle Li loss,c-LisP prelithiation can also improve the battery cyclability by sustained release of low-dosage Li+ions in subsequent cycles,which have been embodied in several full ASSBs by coupling a LiCoO2 cathode with various types of anodes(including graphite,in foil,Sb,and Si anode).Our work provides a universal cathode prelithiation strategy for high-efficiency Li-ion AsSBs.

Commercially Viable Hybrid Li-Ion/Metal Batteries with High Energy Density Realized by Symbiotic Anode and Prelithiated Cathode

The energy density of commercial lithium(Li)ion batteries with graphite anode is reaching the limit.It is believed that directly utilizing Li metal as anode without a host could enhance the battery’s energy density to the maximum extent.However,the poor reversibility and infinite volume change of Li metal hinder the realistic implementation of Li metal in battery community.Herein,a commercially viable hybrid Li-ion/metal battery is realized by a coordinated strategy of symbiotic anode and prelithiated cathode.To be specific,a scalable template-removal method is developed to fabricate the porous graphite layer(PGL),which acts as a symbiotic host for Li ion intercalation and subsequent Li metal deposition due to the enhanced lithiophilicity and sufficient ion-conducting pathways.A continuous dissolution-deintercalation mechanism during delithiation process further ensures the elimination of dead Li.As a result,when the excess plating Li reaches 30%,the PGL could deliver an ultrahigh average Coulombic efficiency of 99.5% for 180 cycles with a capacity of 2.48 m Ah cm^(-2) in traditional carbonate electrolyte.Meanwhile,an air-stable recrystallized lithium oxalate with high specific capacity(514.3 m Ah g^(-1))and moderate operating potential(4.7-5.0 V)is introduced as a sacrificial cathode to compensate the initial loss and provide Li source for subsequent cycles.Based on the prelithiated cathode and initial Li-free symbiotic anode,under a practical-level3 m Ah capacity,the assembled hybrid Li-ion/metal full cell with a P/N ratio(capacity ratio of Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2) to graphite)of 1.3exhibits significantly improved capacity retention after 300 cycles,indicating its great potential for high-energy-density Li batteries.