Sequential Implantation Research Articles

Hyperdoped Si nanocrystals embedded in silica for infrared plasmonics.

We present the experimental realization of plasmonic hyperdoped Si nanocrystals embedded in silica via a combination of sequential low energy ion implantation and rapid thermal annealing. We show that phosphorus dopants are incorporated into the nanocrystal cores at concentrations up to six times higher than P solid solubility in bulk Si by combining 3D mapping with atom probe tomography and analytical transmission electron microscopy. We shed light on the origin of nanocrystal growth at high P doses, which we attribute to Si recoiling atoms generated in the matrix by P implantation, which likely increase Si diffusivity and feed the Si nanocrystals. We show that dopant activation enables partial nanocrystal surface passivation that can be completed by forming gas annealing. Such surface passivation is a critical step in the formation of plasmon resonance, especially for small nanocrystals. We find that the activation rate in these small doped Si nanocrystals is the same as in bulk Si under the same doping conditions.

Hearing Preservation and Spatial Hearing Outcomes After Cochlear Implantation in Children With TMPRSS3 Mutations.

Investigate hearing preservation and spatial hearing outcomes in children with TMPRSS3 mutations who received bilateral cochlear implantation. Longitudinal case series report. Two siblings (ages, 7 and 4 yr) with TMPRSS3 mutations with down-sloping audiograms received sequential bilateral cochlear implantation with hearing preservation with low-frequency acoustic amplification and high-frequency electrical stimulation. Spatial hearing, including speech perception and localization, was assessed at three time points: preoperative, postoperative of first and second cochlear implant (CI). Both children showed low-frequency hearing preservation in unaided, acoustic-only audiograms. Both children demonstrated improvements in speech perception in both quiet and noise after CI activations. The emergence of spatial hearing was observed. Each child's overall speech perception and spatial hearing when listening with bilateral CIs were within the range or better than published group data from children with bilateral CIs of other etiology. Bilateral cochlear implantation with hearing preservation is a viable option for managing hearing loss for pediatric patients with TMPRSS3 mutations.

Predictive Ability of First-Side Cochlear Implant Performance in Adult Sequential Bilateral Cochlear Implantation.

Predictors of second-side cochlear implant performance have not been well studied. We sought to assess whether speech recognition scores from first-side cochlear implant (CI1) could predict second-side cochlear implant (CI2) scores in sequential bilaterally implanted adults. Retrospective review using a prospectively collected database. Academic tertiary care hospital. Fifty-seven adults with postimplantation speech recognition testing performed at least 12 months after CI2. Sequential bilateral CI. CI2 performance at ≥12 months as measured using consonant-nucleus-consonant (CNC) words and AzBio sentences in quiet and +10 dB signal-to-noise ratio (S/N). CI1 performance scores at ≥12 months were independently associated with CI2 performance scores at ≥12 months for CNC words (β = 0.371 [0.136-0.606], p = 0.003), AzBio sentences in quiet (β = 0.614 [0.429-0.80], p < 0.0001), and AzBio +10 dB S/N (β = 0.712 [0.459-0.964], p < 0.0001). CI1 scores on AzBio in quiet at 0 to 6 months were also independently associated with CI2 AzBio in quiet scores at ≥12 months (β = 0.389 [0.004-0.774], p = 0.048). Hearing loss etiology and duration, age at implantation, interval between CI1 and CI2, duration of hearing aid use, and preimplantation speech recognition testing scores were not consistently associated with CI2 scores at ≥12 months. CI1 performance is an independent predictor of second-side performance as measured ≥12 months postimplantation. This may be a clinically useful metric when considering adult sequential bilateral implantation.

School adjustment of adolescents with sequential bilateral cochlear implants in mainstream school.

Little is known about the school adjustment of adolescents with sequential bilateral cochlear implants (CIs) in mainstream educational settings. This study aims to investigate the school adjustment of adolescents with sequential bilateral CIs, in comparison to those of age-matched adolescents with typical hearing (TH), to explore the relationships between individual variables and school adjustment in the bilateral CI group, and to assess the factors leading to strong school adjustment in the bilateral CI group. Twenty-five adolescents with sequential bilateral CIs and 30 adolescents with TH, aged 13-19 years, participated in this study. The adolescents completed the school adjustment scale (SAS). The two groups were not significantly different on overall SAS scores. However, the TH group scored higher on the SAS than the sequential bilateral CI group with regard to communication skills and relationships with peers. In the bilateral CI group, SAS scores significantly correlated with open-set sentence and receptive vocabulary scores. Receptive vocabulary scores were a significant predictive factor for the level of school adjustment for the bilateral CI group. Adolescents who received sequential bilateral CIs adapted well to mainstream schools. However, they did experience barriers to communication and to make friends in mainstream schools, and their level of school adjustment was affected by their receptive vocabulary skills.

Association between lateral wall electrode array insertion parameters and audiological outcomes in bilateral cochlear implantation

PurposeThe aims of this study were to compare speech recognition at different postoperative times for both ears in bilaterally implanted patients and to assess the influence of the time of deafness, frequency-to-place mismatch, angular insertion depth (AID) and angular separation between neighbouring electrode contacts on audiometric outcomes.MethodsThis study was performed at an academic tertiary referral centre. A total of 19 adult patients (6 men, 13 women), who received sequential bilateral implantation with lateral wall electrode arrays, were analysed in retrospective. Statistical analysis was performed using two-sided t test, Wilcoxon test, median test, and Spearman’s correlation.ResultsPostlingually deafened patients (deafness after the age of 10) had a significantly better speech perception (WRS65[CI]) than the perilingually deafened subjects (deafness at the age of 1–10 years) (p < 0.001). Comparison of cochlear duct length between peri- and postlingually deafened subjects showed a slightly significantly smaller cochleae in perilingual patients (p = 0.045). No association between frequency-to-place mismatch as well as angular separation and speech perception could be detected. There was even no significant difference between the both ears in the intraindividual comparison, even if insertion parameters differed.ConclusionThe exact electrode position seems to have less influence on the speech comprehension of CI patients than already established parameters as preoperative speech recognition or duration of deafness.

Sequential percutaneous tricuspid and pulmonary valve implantation in a young child operated previously for Ebstein Anomaly.

We report a successful percutaneous tricuspid valve implantation followed by a percutaneous pulmonary valve implantation in a young child with Ebstein's anomaly of tricuspid valve and pulmonary stenosis who was previously treated surgically at 1 year of age with tricuspid ring annuloplasty and a transannular outflow patch. This article shows the feasibility of sequential implantation of two valves in young patients with severe tricuspid and pulmonary valve insufficiency.

Performance of Sequentially Bilateral Cochlear Implanted Children Who Speak Mandarin

Introduction: Cochlear implantation is an effective treatment for children with deafness. Although the binaural effect of bilateral cochlear implantation on sound localization and speech perception in noisy environments has been demonstrated, the outcome and performance predictors of the second cochlear implant (CI2) remain uncertain for patients receiving sequential implantation. This study evaluated the hearing performance between the first cochlear implant (CI1), CI2, and bilateral cochlear implants (CI1+2) among children with sequential bilateral cochlear implantation. Methods: This single-center retrospective study enrolled 14 children and adolescents aged 8–18 years who underwent sequential bilateral cochlear implantation with a mean interimplant interval of 8.2 years. The Mandarin Lexical Neighborhood Test (M-LNT), the Mandarin Hearing in Noise Test (M-HINT), and the Comprehensive Cochlear Implant Questionnaire (CCIQ) scores of participants were evaluated. Mann-Whitney U tests and Spearman correlation analysis were performed to analyze factors associated with CI2 performance. Results: In the 1-year follow-up period after CI2 implantation, although the M-LNT mean score for CI2 was significantly lower than that for CI1, the M-LNT scores for CI2 and CI1+2 improved significantly over time. In a noisy environment, CI1+2 significantly outperformed CI1 in the M-HINT. The M-LNT score for CI2 was significantly associated with preoperative bimodal fitting, residual hearing of the second implanted ear, and CI2 daily-usage time. Specific to CI2, the CCIQ showed improvement 1 year after CI2 implantation. Conclusion: CI2 improved the hearing performance and quality of life of recipients with longer interimplant intervals, especially in noisy environments, and its efficacy was associated with preoperative bimodal fitting and regular daily use.

Sequential intracorneal ring segment implantation followed by transepithelial phototherapeutic keratectomy and corneal cross-linking

To evaluate the safety and visual outcomes of intrastromal corneal ring segment (ICRS) implantation followed by transepithelial phototherapeutic keratectomy (te-PTK) and corneal cross-linking (CXL) in patients with mild keratoconus. Patients with mildkeratoconusand contact lens intolerance who underwent sequential ICRS implantation followed by phototherapeutic keratectomy and corneal CXL between April 2015 and July 2018 were retrospectively included in the study. Refractive and visual outcomes, satisfaction questionnaire and complications were recorded at the last follow-up (mean 9.5 months postoperatively). Twenty eyes of 17 patients were enrolled, including 5 women and 15 men. The mean time between the two procedures was 16 months. Based on values before the first procedure and 9.5 months after the second procedure, significant improvements were noted in uncorrected distance visual acuity (UDVA) (0.80±0.35 logMAR vs. 0.46±0.38 logMAR), corrected distance visual acuity (CDVA) (0.38±0.23 logMAR vs. 0.13±0.16 logMAR), maximal K (56.11±4 diopters [D] vs. 50.6±3.56 D), mean K (51.87±3.43 D vs. 48.45±2.91 D), cylinder (7.99±3.94 D vs. 4.23±3.49 D), and spherical equivalent (-3.84±3.36 D vs. -0.99±2.15 D) (P<0.01). Among the outcomes, we noted 5 (25%) superficial corneal scarring (haze); 75% of eyes gained>=1 logMAR line of CDVA. In all, 94.5% of patients reported that they were satisfied with their outcomes. Combining ICRS implantation followed by te-PTK and corneal CXL appears to be a safe and effective approach for improving visual outcomes and quality of life in keratoconus patients.

Subtotal Petrosectomy and Cochlear Implantation in Children With Chronic Suppurative Otitis Media: A Single Institutional Experience.

Chronic suppurative otitis media (CSOM) with or without cholesteatoma is a frequent chronic inflammatory condition in children, which may lead to severe hearing loss that affects speech development. Treatment of recurrent CSOM associated with unserviceable hearing requires a specialized approach with regard to disease eradication and hearing rehabilitation. In this study, we investigated the advantages of subtotal petrosectomy (SP) combined with cochlear implantation (CI) in children with CSOM associated with unserviceable hearing and describe our experience with regard to the efficacy of this method, together with a literature review. SP with sequential or simultaneous CI was performed in three children (four ears), and postoperative audiometric data were recorded. The study included two male and one female patient. Mean age at the time of SP was 10.75 years (7-13 years). Sequential implantation was performed in three ears. Facial nerve palsy occurred after SP in one patient. The latest word recognition scores of Cases 1, 2, and 3 were 80% (at 60 dB), 75% (at 60 dB), and 70% (at 50 dB) and 90% (at 50 dB), respectively. SP with CI may be safe and reliable in children with CSOM associated with unserviceable hearing.

Process engineering of GaN power devices via selective-area p-type doping with ion implantation and ultra-high-pressure annealing

P-type doping in selected areas of gallium nitride (GaN) using magnesium (Mg)-ion implantation and subsequent ultra-high-pressure annealing (UHPA) are investigated to improve the performance of vertical GaN power devices. UHPA allows a high-temperature process without decomposition of the GaN surface and virtually complete activation of the implanted Mg ions in GaN. In the present paper, we provide an overview of recent challenges in making UHPA more realistic as an industrial process. Instead of UHPA at more than 1400 °C for a short duration, prolonged UHPA at 1300 °C demonstrates a comparable acceptor activation of Mg-ion-implanted GaN. This can reduce the annealing pressure to approximately 300 MPa and enlarge the processable wafer diameter. The second challenge is controlling the doping profiles in the lateral and vertical directions. We demonstrate fine patterning of the p-type regions, which indicates the limited lateral diffusion of Mg through UHPA. However, controlling the vertical doping profile is challenging. The nitrogen vacancies formed by ion implantation reduce the effective acceptor concentration near the surface, which can be compensated for by sequential nitrogen ion implantation. Defect-assisted Mg diffusion to the deeper region causes a redistribution of the Mg atoms and should be considered in the design of a device. Such anisotropic diffusion of Mg to the c-axis has potential applications in the fabrication of unique vertical device structures such as super junctions.

Speech Perception of Second Cochlear Implant after 6 Years of Age in Prelingually Deaf Children.

Sequential bilateral cochlear implantation in children becomes less effective as the inter-implant interval increases. However, the cause of this and the age at which speech perception becomes impossible are unclear. We examined the cases of 11 prelingually deaf children who underwent unilateral cochlear implantation at our hospitals before the age of 5years old, followed by a second implantation procedure on the contralateral side when they were aged ≥ 6years old (6-12years old). The subjects' hearing thresholds and speech discrimination scores for the second cochlear implant were evaluated at 3 postoperative months and 1-7years. All of the subjects demonstrated improvements in their hearing thresholds to a mean of 30dB HL at 1year. Regarding speech perception, one patient (a 12-year-old), who had developed bilateral hearing loss at 30months of age after contracting mumps, demonstrated a 90% improvement in his speech discrimination score at 1year. However, among the other congenitally deaf children, there were two patients whose speech discrimination scores had improved by ≥ 80% at > 4 postoperative years. The congenitally deaf children exhibited poor speech perception despite showing improved hearing thresholds in the ears that received second cochlear implants. Assuming that the auditory pathway beyond the superior olivary complex remained functional, the reduced speech perception abilities associated with the second cochlear implants may have been attributable to the loss of the spiral ganglion and cochlear nucleus cells due to a lack of auditory input since birth.

Longitudinal Effects of Simultaneous and Sequential Bilateral Cochlear Implantation on Cortical Auditory-Evoked Potentials Recorded at Cz in a Large Cohort of Children.

Auditory development after bilateral cochlear implantation in children has been measured using source localization of multi-channel late latency responses. It is not clear, however, whether this development can be tracked using a more clinically feasible method of recording from one active recording electrode placed at mid-line center of the head (Cz). In this prospective cohort study, cortical auditory-evoked potential responses (CAEPs) were recorded from Cz referenced to each earlobe (Cz-CAEP) from 222 children with bilateral cochlear implant (CI); 128 (mean ± SD age: 2.78 ± 3.30 years) received both CIs in the same surgery (simultaneous group) and 94 (aged 7.72 ± 4.45 years) received a second CI after 4.21 ± 2.98 years of unilateral CI use. We sought to (1) identify cortical development over the first couple of years of bilateral CI use; (2) measure known asymmetries in auditory development between the CIs; and (3) detect the effects of bilateral rather than unilateral CI use. 4556 Cz-CAEPs were recorded across the cohort over 33.50 ± 7.67 months duration of bilateral CI use. Given concerns related to peak picking, amplitude areas were measured across two response time windows (50 to 199 ms and 200 to 400 ms). Results indicated that small response amplitudes occur at initial CI use and amplitudes increase in the negative or positive direction rapidly over the first months of CI use in both time windows. Asymmetries between Cz-CAEPs evoked by each CI were found in the sequential group and reduced with bilateral CI use, particularly in the first time window; these differences increased with longer inter-implant delay. Bilaterally evoked Cz-CAEPs were larger in amplitude than unilateral responses from either CI in the simultaneous group. In the sequential group, bilateral responses were similar to responses from the first implanted side but increased in relative amplitude with bilateral CI use. The Cz-CAEP measures were not able to predict asymmetries or bilateral benefits in speech perception measures. The Cz-CAEP was able to indicate cortical detection of CI input and showed gross morphological changes with bilateral CI use. Findings indicate Cz-CAEPs can be used to identify gross changes in auditory development in children with bilateral CIs, but they are less sensitive to tracking the remaining abnormalities that are measured by multi-channel CAEPs and speech perception testing.

Keratometric Outcomes after Simultaneous versus Sequential Intracorneal Ring Segment Implantation with Femtosecond Laser and Corneal Collagen Crosslinking in Egyptian Patients with Keratoconus and Ectasia.

Keratoconus (KC) is degenerative corneal disorder, with central and paracentral thinning and corneal ectasia. For KC progressive cases, primary treatment included corneal collagen cross linking (CXL) to stabilize coning and intracorneal rings segment (ICRS) to correct visual acuity. The aim of the study is to assess efficacy and safety of ICRS and CXL on one session (Simultaneous) or two sessions (sequential) with maximum of 1 month apart. This Prospective Intervention Comparative research made at Armed forces hospital, Cairo, Egypt from January 2017 to December 2019. Forty patients (60 eyes) with mild to moderate KC were enrolled. Patients sorted into Simultaneous group includes 21 patients (30 eyes) undergo two procedures (ICRS then CXL) at the same session and Sequential group included 19 patients (30 eyes) undergo ICRS then CXL on two sessions with month apart. Patients followed up at end of 1st, 3rd, and 6th months. Assessment included changes in corrected corneal surface irregularities as minimum keratometric 1 (K1), maximum keratometric readings (K2), and mean keratometric (Km) readings. Improvement of K1, K2, and Km in Simulations and Sequential groups achieved at end of 1st-, 3rd-, and 6th-month postoperative versus preoperative. Maximum improvement in Simulations and Sequential groups in K1 achieved at end of 6th and 1st months, in K2 at end of 3rd and 6th months and in Km at end of 1st and 3rd months. Combined ICRS and CXL act safely in one or two sessions and there are no statistically significant variations between results on both methods in keratometric readings.

Phase transitions and He bubble evolution under sequential He ions implantation and Fe ions irradiation: New insight into the irradiation resistant of Ti3AlC2

The phase transitions and He bubble evolution in Ti3AlC2 with the sequential He ions implantation and Fe ions irradiation at room temperature were investigated with grazing incidence X-ray diffraction and transmission electron microscopy. The pre-implanted He makes an obviously effect of suppressing the phase transitions caused by the following Fe ions irradiation. The following Fe ions irradiation was also found to create a competitive effect on the evolution of the pre-formed He bubbles. It can cause not only the growth of He bubbles, but the shrinkage (or re-solution of He bubbles). This will improve the resistance to He bubbles induced damage for Ti3AlC2. Both He ions implantation and Fe ions irradiation actually inhibit each other's irradiation damage to the material. This may play a positive role in reducing irradiation damage to the Ti3AlC2 material, and also provides new insight into irradiation resistance of this material.

Sequential bilateral cochlear implant: long-term speech perception results in children first implanted at an early age

PurposeThe study aims to assess the benefit of sequential bilateral cochlear implantation in children with congenital bilateral profound hearing loss, submitted to the first implant at an early age.MethodsWe enrolled all the bilateral sequential cochlear implanted children who received the first implant within 48 months and the second within 12 years of age at our Institution. The children were submitted to disyllabic word recognition tests and Speech Reception Threshold (SRT) assessment using the OLSA matrix sentence test with the first implanted device (CI1), with the second implanted device (CI2), and with both devices (CIbil). Furthermore, we measured the datalogging of both devices. Then we calculated the binaural SRT gain (b-SRTgain) and checked the correlations between speech perception results and the b-SRTgain with the child’s age at CI1 and CI2, DELTA and the datalogging reports.ResultsWith the bilateral electric stimulation, we found a significant improvement in disyllabic word recognition scores and in SRT. Moreover, the datalogging showed no significant differences in the time of use of CI1 and CI2. We found significant negative correlations between speech perception abilities with CI2 and age at CI2 and DELTA, and between the SRT with CI1 and the b-SRTgain.ConclusionsFrom this study we can conclude that in a sequential CI procedure, even if a short inter-implant delay and lower ages at the second surgery can lead to better speech perception with CI2, children can benefit from bilateral stimulation independently of age at the second surgery and the DELTA.

Benefit of sequential bilateral cochlear implantation in children between 5 to 18 years old: A prospective cohort study.

To determine the benefit of sequential cochlear implantation after a long inter-implantation interval in children with bilateral deafness receiving their second implant between 5 and 18 years of age. Prospective cohort-study. Tertiary multicenter. 85 children with bilateral deafness and unilateral implantation receiving a contralateral cochlear implant at the age of 5 to 18 years. The primary outcomes were speech recognition in quiet and noise (CVC) scores. The secondary outcomes were language outcomes and subjective hearing abilities, all measured before and 12 months after sequential bilateral cochlear implantation. Medians of the paired data were compared using the Wilcoxon signed-rank test. Univariable linear regression analyses was used to analyze associations between variables and performance outcomes. A significant benefit was found for speech recognition in quiet (96% [89-98] vs 91% [85-96]; p < 0.01) and noise (65% [57-75] vs 54% [47-71]; p = 0.01) in the bilateral CI condition compared to unilateral (n = 75, excluded 10 non-users). No benefit was seen for language outcomes. The subjective sound quality score was statistically significant higher in bilateral compared to the unilateral CI condition. Pre-operative residual hearing level in the ear of the second implant, the inter-implant interval and age at time of second implantation was not significantly associated with performance scores. After 12 months of use, sequential bilateral cochlear implantation showed improved speech perception in quiet and noise and improved subjective sound quality outcomes in children despite a great inter-implantation interval (median of 8 years [range 1-16 years]).

HGG-42. Evolutionary selection of key oncogenic alterations in patient-derived models of paediatric diffuse high grade glioma (PDHGG) subtypesin vitro andin vivo

PDHGG are a diverse group of childhood brain tumours comprising multiple subgroups carrying distinct molecular drivers. Patient-derived models accurately recapitulating this underlying biology are critical for mechanistic/preclinical studies aimed at improving patient outcome, however their behaviour over time in the environments in which they are propagated, and how this relates to the human disease, is largely unknown. To explore this, we collected 94 models of PDHGG established as 2D/3D stem cell cultures in vitro, and generated patient-derived xenografts (PDX) in 33/62 specimens implanted orthotopically in vivo. We carried out exome/targeted sequencing, methylation profiling and RNAseq to profile cells through their first 25 passages in culture, and sequential implantation from p0-p2 in mice. In 15/83 cultures, we observed enrichment of gene expression signatures of non-malignant cells over the first 5 passages, with concurrent depletion of somatic mutations/CNAs, excluding them from further study. Validated models retained tumour-matched genotypes, CNAs and driver alterations including H3.3G34R, H3.3/H3.1K27M, BRAF and ACVR1 over time, however subclonal alterations underwent selection in culture which profoundly altered their response to targeted drug treatment. In 6/7 PDGFRA-mutant models, activating mutations were selected against between p5-20 in 2D and/or 3D, whilst MAPK pathway mutations in NF1/PIK3R1 similarly diverged over 15 passages under different growth conditions, resulting in isogenic models with differential signalling, in vivo tumorigenicity, and in vitro sensitivity to multiple MEK inhibitors. In PDXs, serial xenografting reduced the time to tumour formation by up to half, with a concomitant shift in clonal architecture. Multi-region sequencing of diffusely-infiltrating tumours showed selection for alterations such as PIK3CA/NF1 at distant sites, with evidence for convergent evolution of subclonal mutations, as in human tumours. Understanding the evolutionary dynamics of targetable/predictive alterations in PDHGG model systems is key to developing new and effective therapeutic interventions in this highly heterogenous disease.

Effects of Sequential Bilateral Cochlear Implantation in Children: Evidence from Speech-Evoked Cortical Potentials and Tests of Speech Perception

Introduction: Benefits of bilateral cochlear implants (CI) may be compromised by delays to implantation of either ear. This study aimed to evaluate the effects of sequential bilateral CI use in children who received their first CI at young ages, using a clinical set-up. Methods: One-channel cortical auditory evoked potentials and speech perception in quiet and noise were evoked at repeated times (0, 3, 6, 12 months of bilateral CI use) by unilateral and bilateral stimulation in 28 children with early-onset deafness. These children were unilaterally implanted before 3.69 years of age (mean ± SD of 1.98 ± 0.73 years) and received a second CI after 5.13 ± 2.37 years of unilateral CI use. Comparisons between unilaterally evoked responses were used to measure asymmetric function between the ears and comparisons between bilateral responses and each unilateral response were used to measure the bilateral benefit. Results: Chronic bilateral CI promoted changes in cortical auditory responses and speech perception performance; however, large asymmetries were present between the two unilateral responses despite ongoing bilateral CI use. Persistent cortical differences between the two sides at 1 year of bilateral stimulation were predicted by increasing age at the first surgery and inter-implant delay. Larger asymmetries in speech perception occurred with longer inter-implant delays. Bilateral responses were more similar to the unilateral responses from the first rather than the second CI. Conclusion: These findings are consistent with the development of the aural preference syndrome and reinforce the importance of providing bilateral CIs simultaneously or sequentially with very short delays.

Atrioventricular sequential pacemaker implantation inanadult patient with a Fontan circulation.

Atrioventricular sequential pacemaker implantation inanadult patient with a Fontan circulation.

Xenon Ion Implantation Induced Surface Compressive Stress for Preventing Dendrite Penetration in Solid-State Electrolytes.

Solid-state electrolytes (SSEs) have been thrust into the limelight for the revival of energy-dense lithium metal batteries, but still face the challenge of failure caused by the dendrite penetration. Mounting evidence indicates that dendrite penetration is related to the mechanical failure in SSEs, which calls for mechanical engineering to tackle this problem. This work reports a proof of concept that ion implantation induced surface compressive stress enables resistance in the dendrite penetration. A deterministic sequential multiple ion energies implantation is used to generate compressive stress, with implanted Xe ions distributed in a range of 160-600 Å from the surface. The symmetric lithium cells show that pellets with an implantation dose of 1013 Xe cm-2 exhibit stable stripping/plating cycles and extended lifespan, while a lower dose of 1012 Xe cm-2 cannot create sufficient stress to prevent dendrite penetration, and an excessive dose of 1014 Xe cm-2 leads to structural destruction and a decrease in stress. This improved performance is attributed to the induced surface compressive stress balanced over crystal grains, which is confirmed by grazing incidence diffraction techniques. The author's efforts demonstrate the usefulness of surface compressive stress to suppress dendrite penetration, offering more insight into rational stress-strain engineering as opposed to empirical optimization.